pax_global_header00006660000000000000000000000064141664234540014523gustar00rootroot0000000000000052 comment=862afb9f030b26c19ad333ff1af8e3b8b8eefc66 esbuild-0.14.11/000077500000000000000000000000001416642345400133165ustar00rootroot00000000000000esbuild-0.14.11/.editorconfig000066400000000000000000000001311416642345400157660ustar00rootroot00000000000000[*] indent_style = tab indent_size = 2 [*.{js,ts}] indent_style = space indent_size = 2 esbuild-0.14.11/.github/000077500000000000000000000000001416642345400146565ustar00rootroot00000000000000esbuild-0.14.11/.github/workflows/000077500000000000000000000000001416642345400167135ustar00rootroot00000000000000esbuild-0.14.11/.github/workflows/ci.yml000066400000000000000000000076041416642345400200400ustar00rootroot00000000000000name: CI on: push: branches: ['*'] pull_request: branches: ['*'] jobs: esbuild: name: esbuild CI runs-on: ${{ matrix.os }} strategy: matrix: os: [ubuntu-latest, macos-latest, windows-latest] steps: - name: Set up Go 1.x uses: actions/setup-go@v2 with: go-version: 1.17.5 id: go - name: Setup Node.js environment uses: actions/setup-node@v1.4.4 with: node-version: 16 - name: Setup Deno 1.x uses: denoland/setup-deno@main with: deno-version: v1.x - name: Check out code into the Go module directory uses: actions/checkout@v2 - name: go test run: go test -race ./internal/... - name: go vet run: go vet ./cmd/... ./internal/... ./pkg/... - name: Deno Tests # Deno tests currently don't run on Windows because of "esbuild" vs. # "esbuild.exe" in the test harness. This should be fixed... if: matrix.os != 'windows-latest' run: make test-deno - name: Test for path/filepath if: matrix.os == 'ubuntu-latest' run: make no-filepath - name: Make sure "check-go-version" works if: matrix.os != 'windows-latest' run: make check-go-version - name: go fmt if: matrix.os == 'macos-latest' run: make fmt-go - name: npm ci run: cd scripts && npm ci - name: Register Test (ESBUILD_WORKER_THREADS=0) if: matrix.os != 'windows-latest' run: ESBUILD_WORKER_THREADS=0 node scripts/register-test.js - name: Register Test run: node scripts/register-test.js - name: Verify Source Map run: node scripts/verify-source-map.js - name: E2E Tests run: node scripts/end-to-end-tests.js - name: JS API Tests (ESBUILD_WORKER_THREADS=0) if: matrix.os != 'windows-latest' run: ESBUILD_WORKER_THREADS=0 node scripts/js-api-tests.js - name: JS API Tests run: node scripts/js-api-tests.js - name: NodeJS Unref Tests run: node scripts/node-unref-tests.js - name: Plugin Tests run: node scripts/plugin-tests.js - name: TypeScript Type Definition Tests if: matrix.os == 'ubuntu-latest' run: node scripts/ts-type-tests.js - name: JS API Type Check if: matrix.os == 'ubuntu-latest' run: make lib-typecheck - name: WebAssembly API Tests (browser) if: matrix.os == 'ubuntu-latest' run: make test-wasm-browser - name: WebAssembly API Tests (node) if: matrix.os == 'ubuntu-latest' run: make test-wasm-node - name: WebAssembly API Tests (node) if: matrix.os != 'ubuntu-latest' run: node scripts/wasm-tests.js - name: Sucrase Tests if: matrix.os == 'ubuntu-latest' run: make test-sucrase - name: Esprima Tests if: matrix.os == 'ubuntu-latest' run: make test-esprima - name: Preact Splitting Tests if: matrix.os == 'ubuntu-latest' run: make test-preact-splitting - name: Uglify Tests if: matrix.os == 'ubuntu-latest' run: CI=1 make uglify - name: Rollup Tests if: matrix.os == 'ubuntu-latest' run: make test-rollup - name: Check the unicode table generator if: matrix.os == 'ubuntu-latest' run: cd scripts && node gen-unicode-table.js esbuild-old-golang: name: esbuild CI (old Go version) runs-on: ubuntu-latest steps: - name: Set up Go 1.13 (the minimum required Go version for esbuild) uses: actions/setup-go@v2 with: go-version: 1.13 id: go - name: Check out code into the Go module directory uses: actions/checkout@v2 - name: go build run: go build ./cmd/esbuild - name: go test run: go test ./internal/... esbuild-0.14.11/.github/workflows/e2e.yml000066400000000000000000000011671416642345400201160ustar00rootroot00000000000000name: End-to-end install tests on: schedule: - cron: '0 */6 * * *' jobs: validate: runs-on: ubuntu-latest steps: - name: Checkout code uses: actions/checkout@v2 - name: Setup Node.js environment uses: actions/setup-node@v1.4.4 with: node-version: 16 - name: Test npm run: | npm i -g npm@next-7 time make test-e2e-npm - name: Test pnpm run: | npm i -g pnpm@next time make test-e2e-pnpm - name: Test yarn run: | npm i -g yarn@latest time make test-e2e-yarn-berry esbuild-0.14.11/.github/workflows/release.yml000066400000000000000000000014221416642345400210550ustar00rootroot00000000000000name: Release on: push: tags: ['v*'] jobs: release: runs-on: ubuntu-latest steps: - name: Checkout code uses: actions/checkout@v2 - name: Extract changelog run: | CHANGELOG=$(awk -v ver=$(cat version.txt) '/^## / { if (p) { exit }; if ($2 == ver) { p=1; next} } p' CHANGELOG.md) echo "CHANGELOG<> $GITHUB_ENV echo "$CHANGELOG" >> $GITHUB_ENV echo "EOF" >> $GITHUB_ENV - name: Create GitHub Release uses: actions/create-release@v1 env: GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }} with: tag_name: ${{ github.ref }} release_name: ${{ github.ref }} body: ${{ env.CHANGELOG }} draft: false prerelease: false esbuild-0.14.11/.gitignore000066400000000000000000000005161416642345400153100ustar00rootroot00000000000000.DS_Store /bench/ /demo/ /deno/ /esbuild /github/ /npm/esbuild-wasm/browser.js /npm/esbuild-wasm/esbuild.wasm /npm/esbuild-wasm/esm/ /npm/esbuild-wasm/exit0.js /npm/esbuild-wasm/lib/ /npm/esbuild-wasm/wasm_exec.js /npm/esbuild/install.js /npm/esbuild/lib/ /require/*/bench/ /require/*/demo/ /scripts/.*/ bin esbuild.exe node_modules/ esbuild-0.14.11/CHANGELOG.md000066400000000000000000024465521416642345400151510ustar00rootroot00000000000000# Changelog ## 0.14.11 * Fix a bug with enum inlining ([#1903](https://github.com/evanw/esbuild/issues/1903)) The new TypeScript enum inlining behavior had a bug where it worked correctly if you used `export enum Foo` but not if you used `enum Foo` and then later `export { Foo }`. This release fixes the bug so enum inlining now works correctly in this case. * Warn about `module.exports.foo = ...` in ESM ([#1907](https://github.com/evanw/esbuild/issues/1907)) The `module` variable is treated as a global variable reference instead of as a CommonJS module reference in ESM code, which can cause problems for people that try to use both CommonJS and ESM exports in the same file. There has been a warning about this since version 0.14.9. However, the warning only covered cases like `exports.foo = bar` and `module.exports = bar` but not `module.exports.foo = bar`. This last case is now handled; ``` ▲ [WARNING] The CommonJS "module" variable is treated as a global variable in an ECMAScript module and may not work as expected example.ts:2:0: 2 │ module.exports.b = 1 ╵ ~~~~~~ This file is considered to be an ECMAScript module because of the "export" keyword here: example.ts:1:0: 1 │ export let a = 1 ╵ ~~~~~~ ``` * Enable esbuild's CLI with Deno ([#1913](https://github.com/evanw/esbuild/issues/1913)) This release allows you to use Deno as an esbuild installer, without also needing to use esbuild's JavaScript API. You can now use esbuild's CLI with Deno: ``` deno run --allow-all "https://deno.land/x/esbuild@v0.14.11/mod.js" --version ``` ## 0.14.10 * Enable tree shaking of classes with lowered static fields ([#175](https://github.com/evanw/esbuild/issues/175)) If the configured target environment doesn't support static class fields, they are converted into a call to esbuild's `__publicField` function instead. However, esbuild's tree-shaking pass treated this call as a side effect, which meant that all classes with static fields were ineligible for tree shaking. This release fixes the problem by explicitly ignoring calls to the `__publicField` function during tree shaking side-effect determination. Tree shaking is now enabled for these classes: ```js // Original code class Foo { static foo = 'foo' } class Bar { static bar = 'bar' } new Bar() // Old output (with --tree-shaking=true --target=es6) class Foo { } __publicField(Foo, "foo", "foo"); class Bar { } __publicField(Bar, "bar", "bar"); new Bar(); // New output (with --tree-shaking=true --target=es6) class Bar { } __publicField(Bar, "bar", "bar"); new Bar(); ``` * Treat `--define:foo=undefined` as an undefined literal instead of an identifier ([#1407](https://github.com/evanw/esbuild/issues/1407)) References to the global variable `undefined` are automatically replaced with the literal value for undefined, which appears as `void 0` when printed. This allows for additional optimizations such as collapsing `undefined ?? bar` into just `bar`. However, this substitution was not done for values specified via `--define:`. As a result, esbuild could potentially miss out on certain optimizations in these cases. With this release, it's now possible to use `--define:` to substitute something with an undefined literal: ```js // Original code let win = typeof window !== 'undefined' ? window : {} // Old output (with --define:window=undefined --minify) let win=typeof undefined!="undefined"?undefined:{}; // New output (with --define:window=undefined --minify) let win={}; ``` * Add the `--drop:debugger` flag ([#1809](https://github.com/evanw/esbuild/issues/1809)) Passing this flag causes all [`debugger;` statements](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/debugger) to be removed from the output. This is similar to the `drop_debugger: true` flag available in the popular UglifyJS and Terser JavaScript minifiers. * Add the `--drop:console` flag ([#28](https://github.com/evanw/esbuild/issues/28)) Passing this flag causes all [`console.xyz()` API calls](https://developer.mozilla.org/en-US/docs/Web/API/console#methods) to be removed from the output. This is similar to the `drop_console: true` flag available in the popular UglifyJS and Terser JavaScript minifiers. WARNING: Using this flag can introduce bugs into your code! This flag removes the entire call expression including all call arguments. If any of those arguments had important side effects, using this flag will change the behavior of your code. Be very careful when using this flag. If you want to remove console API calls without removing arguments with side effects (which does not introduce bugs), you should mark the relevant API calls as pure instead like this: `--pure:console.log --minify`. * Inline calls to certain no-op functions when minifying ([#290](https://github.com/evanw/esbuild/issues/290), [#907](https://github.com/evanw/esbuild/issues/907)) This release makes esbuild inline two types of no-op functions: empty functions and identity functions. These most commonly arise when most of the function body is eliminated as dead code. In the examples below, this happens because we use `--define:window.DEBUG=false` to cause dead code elimination inside the function body of the resulting `if (false)` statement. This inlining is a small code size and performance win but, more importantly, it allows for people to use these features to add useful abstractions that improve the development experience without needing to worry about the run-time performance impact. An identity function is a function that just returns its argument. Here's an example of inlining an identity function: ```js // Original code function logCalls(fn) { if (window.DEBUG) return function(...args) { console.log('calling', fn.name, 'with', args) return fn.apply(this, args) } return fn } export const foo = logCalls(function foo() {}) // Old output (with --minify --define:window.DEBUG=false --tree-shaking=true) function o(n){return n}export const foo=o(function(){}); // New output (with --minify --define:window.DEBUG=false --tree-shaking=true) export const foo=function(){}; ``` An empty function is a function with an empty body. Here's an example of inlining an empty function: ```ts // Original code function assertNotNull(val: Object | null): asserts val is Object { if (window.DEBUG && val === null) throw new Error('null assertion failed'); } export const val = getFoo(); assertNotNull(val); console.log(val.bar); // Old output (with --minify --define:window.DEBUG=false --tree-shaking=true) function l(o){}export const val=getFoo();l(val);console.log(val.bar); // New output (with --minify --define:window.DEBUG=false --tree-shaking=true) export const val=getFoo();console.log(val.bar); ``` To get this behavior you'll need to use the `function` keyword to define your function since that causes the definition to be hoisted, which eliminates concerns around initialization order. These features also work across modules, so functions are still inlined even if the definition of the function is in a separate module from the call to the function. To get cross-module function inlining to work, you'll need to have bundling enabled and use the `import` and `export` keywords to access the function so that esbuild can see which functions are called. And all of this has been added without an observable impact to compile times. I previously wasn't able to add this to esbuild easily because of esbuild's low-pass compilation approach. The compiler only does three full passes over the data for speed. The passes are roughly for parsing, binding, and printing. It's only possible to inline something after binding but it needs to be inlined before printing. Also the way module linking was done made it difficult to roll back uses of symbols that were inlined, so the symbol definitions were not tree shaken even when they became unused due to inlining. The linking issue was somewhat resolved when I fixed #128 in the previous release. To implement cross-module inlining of TypeScript enums, I came up with a hack to defer certain symbol uses until the linking phase, which happens after binding but before printing. Another hack is that inlining of TypeScript enums is done directly in the printer to avoid needing another pass. The possibility of these two hacks has unblocked these simple function inlining use cases that are now handled. This isn't a fully general approach because optimal inlining is recursive. Inlining something may open up further inlining opportunities, which either requires multiple iterations or a worklist algorithm, both of which don't work when doing late-stage inlining in the printer. But the function inlining that esbuild now implements is still useful even though it's one level deep, and so I believe it's still worth adding. ## 0.14.9 * Implement cross-module tree shaking of TypeScript enum values ([#128](https://github.com/evanw/esbuild/issues/128)) If your bundle uses TypeScript enums across multiple files, esbuild is able to inline the enum values as long as you export and import the enum using the ES module `export` and `import` keywords. However, this previously still left the definition of the enum in the bundle even when it wasn't used anymore. This was because esbuild's tree shaking (i.e. dead code elimination) is based on information recorded during parsing, and at that point we don't know which imported symbols are inlined enum values and which aren't. With this release, esbuild will now remove enum definitions that become unused due to cross-module enum value inlining. Property accesses off of imported symbols are now tracked separately during parsing and then resolved during linking once all inlined enum values are known. This behavior change means esbuild's support for cross-module inlining of TypeScript enums is now finally complete. Here's an example: ```js // entry.ts import { Foo } from './enum' console.log(Foo.Bar) // enum.ts export enum Foo { Bar } ``` Bundling the example code above now results in the enum definition being completely removed from the bundle: ```js // Old output (with --bundle --minify --format=esm) var r=(o=>(o[o.Bar=0]="Bar",o))(r||{});console.log(0); // New output (with --bundle --minify --format=esm) console.log(0); ``` * Fix a regression with `export {} from` and CommonJS ([#1890](https://github.com/evanw/esbuild/issues/1890)) This release fixes a regression that was introduced by the change in 0.14.7 that avoids calling the `__toESM` wrapper for import statements that are converted to `require` calls and that don't use the `default` or `__esModule` export names. The previous change was correct for the `import {} from` syntax but not for the `export {} from` syntax, which meant that in certain cases with re-exported values, the value of the `default` import could be different than expected. This release fixes the regression. * Warn about using `module` or `exports` in ESM code ([#1887](https://github.com/evanw/esbuild/issues/1887)) CommonJS export variables cannot be referenced in ESM code. If you do this, they are treated as global variables instead. This release includes a warning for people that try to use both CommonJS and ES module export styles in the same file. Here's an example: ```ts export enum Something { a, b, } module.exports = { a: 1, b: 2 } ``` Running esbuild on that code now generates a warning that looks like this: ``` ▲ [WARNING] The CommonJS "module" variable is treated as a global variable in an ECMAScript module and may not work as expected example.ts:5:0: 5 │ module.exports = { a: 1, b: 2 } ╵ ~~~~~~ This file is considered to be an ECMAScript module because of the "export" keyword here: example.ts:1:0: 1 │ export enum Something { ╵ ~~~~~~ ``` ## 0.14.8 * Add a `resolve` API for plugins ([#641](https://github.com/evanw/esbuild/issues/641), [#1652](https://github.com/evanw/esbuild/issues/1652)) Plugins now have access to a new API called `resolve` that runs esbuild's path resolution logic and returns the result to the caller. This lets you write plugins that can reuse esbuild's complex built-in path resolution logic to change the inputs and/or adjust the outputs. Here's an example: ```js let examplePlugin = { name: 'example', setup(build) { build.onResolve({ filter: /^example$/ }, async () => { const result = await build.resolve('./foo', { resolveDir: '/bar' }) if (result.errors.length > 0) return result return { ...result, external: true } }) }, } ``` This plugin intercepts imports to the path `example`, tells esbuild to resolve the import `./foo` in the directory `/bar`, and then forces whatever path esbuild returns to be considered external. Here are some additional details: * If you don't pass the optional `resolveDir` parameter, esbuild will still run `onResolve` plugin callbacks but will not attempt any path resolution itself. All of esbuild's path resolution logic depends on the `resolveDir` parameter including looking for packages in `node_modules` directories (since it needs to know where those `node_modules` directories might be). * If you want to resolve a file name in a specific directory, make sure the input path starts with `./`. Otherwise the input path will be treated as a package path instead of a relative path. This behavior is identical to esbuild's normal path resolution logic. * If path resolution fails, the `errors` property on the returned object will be a non-empty array containing the error information. This function does not always throw an error when it fails. You need to check for errors after calling it. * The behavior of this function depends on the build configuration. That's why it's a property of the `build` object instead of being a top-level API call. This also means you can't call it until all plugin `setup` functions have finished since these give plugins the opportunity to adjust the build configuration before it's frozen at the start of the build. So the new `resolve` function is going to be most useful inside your `onResolve` and/or `onLoad` callbacks. * There is currently no attempt made to detect infinite path resolution loops. Calling `resolve` from within `onResolve` with the same parameters is almost certainly a bad idea. * Avoid the CJS-to-ESM wrapper in some cases ([#1831](https://github.com/evanw/esbuild/issues/1831)) Import statements are converted into `require()` calls when the output format is set to CommonJS. To convert from CommonJS semantics to ES module semantics, esbuild wraps the return value in a call to esbuild's `__toESM()` helper function. However, the conversion is only needed if it's possible that the exports named `default` or `__esModule` could be accessed. This release avoids calling this helper function in cases where esbuild knows it's impossible for the `default` or `__esModule` exports to be accessed, which results in smaller and faster code. To get this behavior, you have to use the `import {} from` import syntax: ```js // Original code import { readFile } from "fs"; readFile(); // Old output (with --format=cjs) var __toESM = (module, isNodeMode) => { ... }; var import_fs = __toESM(require("fs")); (0, import_fs.readFile)(); // New output (with --format=cjs) var import_fs = require("fs"); (0, import_fs.readFile)(); ``` * Strip overwritten function declarations when minifying ([#610](https://github.com/evanw/esbuild/issues/610)) JavaScript allows functions to be re-declared, with each declaration overwriting the previous declaration. This type of code can sometimes be emitted by automatic code generators. With this release, esbuild now takes this behavior into account when minifying to drop all but the last declaration for a given function: ```js // Original code function foo() { console.log(1) } function foo() { console.log(2) } // Old output (with --minify) function foo(){console.log(1)}function foo(){console.log(2)} // New output (with --minify) function foo(){console.log(2)} ``` * Add support for the Linux IBM Z 64-bit Big Endian platform ([#1864](https://github.com/evanw/esbuild/pull/1864)) With this release, the esbuild package now includes a Linux binary executable for the IBM System/390 64-bit architecture. This new platform was contributed by [@shahidhs-ibm](https://github.com/shahidhs-ibm). * Allow whitespace around `:` in JSX elements ([#1877](https://github.com/evanw/esbuild/issues/1877)) This release allows you to write the JSX `` as `` instead. Doing this is not forbidden by [the JSX specification](https://facebook.github.io/jsx/). While this doesn't work in TypeScript, it does work with other JSX parsers in the ecosystem, so support for this has been added to esbuild. ## 0.14.7 * Cross-module inlining of TypeScript `enum` constants ([#128](https://github.com/evanw/esbuild/issues/128)) This release adds inlining of TypeScript `enum` constants across separate modules. It activates when bundling is enabled and when the enum is exported via the `export` keyword and imported via the `import` keyword: ```ts // foo.ts export enum Foo { Bar } // bar.ts import { Foo } from './foo.ts' console.log(Foo.Bar) ``` The access to `Foo.Bar` will now be compiled into `0 /* Bar */` even though the enum is defined in a separate file. This inlining was added without adding another pass (which would have introduced a speed penalty) by splitting the code for the inlining between the existing parsing and printing passes. Enum inlining is active whether or not you use `enum` or `const enum` because it improves performance. To demonstrate the performance improvement, I compared the performance of the TypeScript compiler built by bundling the TypeScript compiler source code with esbuild before and after this change. The speed of the compiler was measured by using it to type check a small TypeScript code base. Here are the results: | | `tsc` | with esbuild 0.14.6 | with esbuild 0.14.7 | |------|-------|---------------------|---------------------| | Time | 2.96s | 3.45s | 2.95s | As you can see, enum inlining gives around a 15% speedup, which puts the esbuild-bundled version at the same speed as the offical TypeScript compiler build (the `tsc` column)! The specifics of the benchmark aren't important here since it's just a demonstration of how enum inlining can affect performance. But if you're wondering, I type checked the [Rollup](https://github.com/rollup/rollup) code base using a work-in-progress branch of the TypeScript compiler that's part of the ongoing effort to convert their use of namespaces into ES modules. * Mark node built-in modules as having no side effects ([#705](https://github.com/evanw/esbuild/issues/705)) This release marks node built-in modules such as `fs` as being side-effect free. That means unused imports to these modules are now removed when bundling, which sometimes results in slightly smaller code. For example: ```js // Original code import fs from 'fs'; import path from 'path'; console.log(path.delimiter); // Old output (with --bundle --minify --platform=node --format=esm) import"fs";import o from"path";console.log(o.delimiter); // New output (with --bundle --minify --platform=node --format=esm) import o from"path";console.log(o.delimiter); ``` Note that these modules are only automatically considered side-effect when bundling for node, since they are only known to be side-effect free imports in that environment. However, you can customize this behavior with a plugin by returning `external: true` and `sideEffects: false` in an `onResolve` callback for whatever paths you want to be treated this way. * Recover from a stray top-level `}` in CSS ([#1876](https://github.com/evanw/esbuild/pull/1876)) This release fixes a bug where a stray `}` at the top-level of a CSS file would incorrectly truncate the remainder of the file in the output (although not without a warning). With this release, the remainder of the file is now still parsed and printed: ```css /* Original code */ .red { color: red; } } .blue { color: blue; } .green { color: green; } /* Old output (with --minify) */ .red{color:red} /* New output (with --minify) */ .red{color:red}} .blue{color:#00f}.green{color:green} ``` This fix was contributed by [@sbfaulkner](https://github.com/sbfaulkner). ## 0.14.6 * Fix a minifier bug with BigInt literals Previously expression simplification optimizations in the minifier incorrectly assumed that numeric operators always return numbers. This used to be true but has no longer been true since the introduction of BigInt literals in ES2020. Now numeric operators can return either a number or a BigInt depending on the arguments. This oversight could potentially have resulted in behavior changes. For example, this code printed `false` before being minified and `true` after being minified because esbuild shortened `===` to `==` under the false assumption that both operands were numbers: ```js var x = 0; console.log((x ? 2 : -1n) === -1); ``` The type checking logic has been rewritten to take into account BigInt literals in this release, so this incorrect simplification is no longer applied. * Enable removal of certain unused template literals ([#1853](https://github.com/evanw/esbuild/issues/1853)) This release contains improvements to the minification of unused template literals containing primitive values: ```js // Original code `${1}${2}${3}`; `${x ? 1 : 2}${y}`; // Old output (with --minify) ""+1+2+3,""+(x?1:2)+y; // New output (with --minify) x,`${y}`; ``` This can arise when the template literals are nested inside of another function call that was determined to be unnecessary such as an unused call to a function marked with the `/* @__PURE__ */` pragma. This release also fixes a bug with this transformation where minifying the unused expression `` `foo ${bar}` `` into `"" + bar` changed the meaning of the expression. Template string interpolation always calls `toString` while string addition may call `valueOf` instead. This unused expression is now minified to `` `${bar}` ``, which is slightly longer but which avoids the behavior change. * Allow `keyof`/`readonly`/`infer` in TypeScript index signatures ([#1859](https://github.com/evanw/esbuild/pull/1859)) This release fixes a bug that prevented these keywords from being used as names in index signatures. The following TypeScript code was previously rejected, but is now accepted: ```ts interface Foo { [keyof: string]: number } ``` This fix was contributed by [@magic-akari](https://github.com/magic-akari). * Avoid warning about `import.meta` if it's replaced ([#1868](https://github.com/evanw/esbuild/issues/1868)) It's possible to replace the `import.meta` expression using the `--define:` feature. Previously doing that still warned that the `import.meta` syntax was not supported when targeting ES5. With this release, there will no longer be a warning in this case. ## 0.14.5 * Fix an issue with the publishing script This release fixes a missing dependency issue in the publishing script where it was previously possible for the published binary executable to have an incorrect version number. ## 0.14.4 * Adjust esbuild's handling of `default` exports and the `__esModule` marker ([#532](https://github.com/evanw/esbuild/issues/532), [#1591](https://github.com/evanw/esbuild/issues/1591), [#1719](https://github.com/evanw/esbuild/issues/1719)) This change requires some background for context. Here's the history to the best of my understanding: When the ECMAScript module `import`/`export` syntax was being developed, the CommonJS module format (used in Node.js) was already widely in use. Because of this the export name called `default` was given special a syntax. Instead of writing `import { default as foo } from 'bar'` you can just write `import foo from 'bar'`. The idea was that when ECMAScript modules (a.k.a. ES modules) were introduced, you could import existing CommonJS modules using the new import syntax for compatibility. Since CommonJS module exports are dynamic while ES module exports are static, it's not generally possible to determine a CommonJS module's export names at module instantiation time since the code hasn't been evaluated yet. So the value of `module.exports` is just exported as the `default` export and the special `default` import syntax gives you easy access to `module.exports` (i.e. `const foo = require('bar')` is the same as `import foo from 'bar'`). However, it took a while for ES module syntax to be supported natively by JavaScript runtimes, and people still wanted to start using ES module syntax in the meantime. The [Babel](https://babeljs.io/) JavaScript compiler let you do this. You could transform each ES module file into a CommonJS module file that behaved the same. However, this transformation has a problem: emulating the `import` syntax accurately as described above means that `export default 0` and `import foo from 'bar'` will no longer line up when transformed to CommonJS. The code `export default 0` turns into `module.exports.default = 0` and the code `import foo from 'bar'` turns into `const foo = require('bar')`, meaning `foo` is `0` before the transformation but `foo` is `{ default: 0 }` after the transformation. To fix this, Babel sets the property `__esModule` to true as a signal to itself when it converts an ES module to a CommonJS module. Then, when importing a `default` export, it can know to use the value of `module.exports.default` instead of `module.exports` to make sure the behavior of the CommonJS modules correctly matches the behavior of the original ES modules. This fix has been widely adopted across the ecosystem and has made it into other tools such as TypeScript and even esbuild. However, when Node.js finally released their ES module implementation, they went with the original implementation where the `default` export is always `module.exports`, which broke compatibility with the existing ecosystem of ES modules that had been cross-compiled into CommonJS modules by Babel. You now have to either add or remove an additional `.default` property depending on whether your code needs to run in a Node environment or in a Babel environment, which created an interoperability headache. In addition, JavaScript tools such as esbuild now need to guess whether you want Node-style or Babel-style `default` imports. There's no way for a tool to know with certainty which one a given file is expecting and if your tool guesses wrong, your code will break. This release changes esbuild's heuristics around `default` exports and the `__esModule` marker to attempt to improve compatibility with Webpack and Node, which is what most packages are tuned for. The behavior changes are as follows: Old behavior: * If an `import` statement is used to load a CommonJS file and a) `module.exports` is an object, b) `module.exports.__esModule` is truthy, and c) the property `default` exists in `module.exports`, then esbuild would set the `default` export to `module.exports.default` (like Babel). Otherwise the `default` export was set to `module.exports` (like Node). * If a `require` call is used to load an ES module file, the returned module namespace object had the `__esModule` property set to true. This behaved as if the ES module had been converted to CommonJS via a Babel-compatible transformation. * The `__esModule` marker could inconsistently appear on module namespace objects (i.e. `import * as`) when writing pure ESM code. Specifically, if a module namespace object was materialized then the `__esModule` marker was present, but if it was optimized away then the `__esModule` marker was absent. * It was not allowed to create an ES module export named `__esModule`. This avoided generating code that might break due to the inconsistency mentioned above, and also avoided issues with duplicate definitions of `__esModule`. New behavior: * If an `import` statement is used to load a CommonJS file and a) `module.exports` is an object, b) `module.exports.__esModule` is truthy, and c) the file name does not end in either `.mjs` or `.mts` and the `package.json` file does not contain `"type": "module"`, then esbuild will set the `default` export to `module.exports.default` (like Babel). Otherwise the `default` export is set to `module.exports` (like Node). Note that this means the `default` export may now be undefined in situations where it previously wasn't undefined. This matches Webpack's behavior so it should hopefully be more compatible. Also note that this means import behavior now depends on the file extension and on the contents of `package.json`. This also matches Webpack's behavior to hopefully improve compatibility. * If a `require` call is used to load an ES module file, the returned module namespace object has the `__esModule` property set to `true`. This behaves as if the ES module had been converted to CommonJS via a Babel-compatible transformation. * If an `import` statement or `import()` expression is used to load an ES module, the `__esModule` marker should now never be present on the module namespace object. This frees up the `__esModule` export name for use with ES modules. * It's now allowed to use `__esModule` as a normal export name in an ES module. This property will be accessible to other ES modules but will not be accessible to code that loads the ES module using `require`, where they will observe the property set to `true` instead. ## 0.14.3 * Pass the current esbuild instance to JS plugins ([#1790](https://github.com/evanw/esbuild/issues/1790)) Previously JS plugins that wanted to run esbuild had to `require('esbuild')` to get the esbuild object. However, that could potentially result in a different version of esbuild. This is also more complicated to do outside of node (such as within a browser). With this release, the current esbuild instance is now passed to JS plugins as the `esbuild` property: ```js let examplePlugin = { name: 'example', setup(build) { console.log(build.esbuild.version) console.log(build.esbuild.transformSync('1+2')) }, } ``` * Disable `calc()` transform for results with non-finite numbers ([#1839](https://github.com/evanw/esbuild/issues/1839)) This release disables minification of `calc()` expressions when the result contains `NaN`, `-Infinity`, or `Infinity`. These numbers are valid inside of `calc()` expressions but not outside of them, so the `calc()` expression must be preserved in these cases. * Move `"use strict"` before injected shim imports ([#1837](https://github.com/evanw/esbuild/issues/1837)) If a CommonJS file contains a `"use strict"` directive, it could potentially be unintentionally disabled by esbuild when using the "inject" feature when bundling is enabled. This is because the inject feature was inserting a call to the initializer for the injected file before the `"use strict"` directive. In JavaScript, directives do not apply if they come after a non-directive statement. This release fixes the problem by moving the `"use strict"` directive before the initializer for the injected file so it isn't accidentally disabled. * Pass the ignored path query/hash suffix to `onLoad` plugins ([#1827](https://github.com/evanw/esbuild/issues/1827)) The built-in `onResolve` handler that comes with esbuild can strip the query/hash suffix off of a path during path resolution. For example, `url("fonts/icons.eot?#iefix")` can be resolved to the file `fonts/icons.eot`. For context, IE8 has a bug where it considers the font face URL to extend to the last `)` instead of the first `)`. In the example below, IE8 thinks the URL for the font is `Example.eot?#iefix') format('eot'), url('Example.ttf') format('truetype` so by adding `?#iefix`, IE8 thinks the URL has a path of `Example.eot` and a query string of `?#iefix') format('eot...` and can load the font file: ```css @font-face { font-family: 'Example'; src: url('Example.eot?#iefix') format('eot'), url('Example.ttf') format('truetype'); } ``` However, the suffix is not currently passed to esbuild and plugins may want to use this suffix for something. Previously plugins had to add their own `onResolve` handler if they wanted to use the query suffix. With this release, the suffix can now be returned by plugins from `onResolve` and is now passed to plugins in `onLoad`: ```js let examplePlugin = { name: 'example', setup(build) { build.onResolve({ filter: /.*/ }, args => { return { path: args.path, suffix: '?#iefix' } }) build.onLoad({ filter: /.*/ }, args => { console.log({ path: args.path, suffix: args.suffix }) }) }, } ``` The suffix is deliberately not included in the path that's provided to plugins because most plugins won't know to handle this strange edge case and would likely break. Keeping the suffix out of the path means that plugins can opt-in to handling this edge case if they want to, and plugins that aren't aware of this edge case will likely still do something reasonable. ## 0.14.2 * Add `[ext]` placeholder for path templates ([#1799](https://github.com/evanw/esbuild/pull/1799)) This release adds the `[ext]` placeholder to the `--entry-names=`, `--chunk-names=`, and `--asset-names=` configuration options. The `[ext]` placeholder takes the value of the file extension without the leading `.`, and can be used to place output files with different file extensions into different folders. For example, `--asset-names=assets/[ext]/[name]-[hash]` might generate an output path of `assets/png/image-LSAMBFUD.png`. This feature was contributed by [@LukeSheard](https://github.com/LukeSheard). * Disable star-to-clause transform for external imports ([#1801](https://github.com/evanw/esbuild/issues/1801)) When bundling is enabled, esbuild automatically transforms `import * as x from 'y'; x.z()` into `import {z} as 'y'; z()` to improve tree shaking. This avoids needing to create the import namespace object `x` if it's unnecessary, which can result in the removal of large amounts of unused code. However, this transform shouldn't be done for external imports because that incorrectly changes the semantics of the import. If the export `z` doesn't exist in the previous example, the value `x.z` is a property access that is undefined at run-time, but the value `z` is an import error that will prevent the code from running entirely. This release fixes the problem by avoiding doing this transform for external imports: ```js // Original code import * as x from 'y'; x.z(); // Old output (with --bundle --format=esm --external:y) import { z } from "y"; z(); // New output (with --bundle --format=esm --external:y) import * as x from "y"; x.z(); ``` * Disable `calc()` transform for numbers with many fractional digits ([#1821](https://github.com/evanw/esbuild/issues/1821)) Version 0.13.12 introduced simplification of `calc()` expressions in CSS when minifying. For example, `calc(100% / 4)` turns into `25%`. However, this is problematic for numbers with many fractional digits because either the number is printed with reduced precision, which is inaccurate, or the number is printed with full precision, which could be longer than the original expression. For example, turning `calc(100% / 3)` into `33.33333%` is inaccurate and turning it into `33.333333333333336%` likely isn't desired. In this release, minification of `calc()` is now disabled when any number in the result cannot be represented to full precision with at most five fractional digits. * Fix an edge case with `catch` scope handling ([#1812](https://github.com/evanw/esbuild/issues/1812)) This release fixes a subtle edge case with `catch` scope and destructuring assignment. Identifiers in computed properties and/or default values inside the destructuring binding pattern should reference the outer scope, not the inner scope. The fix was to split the destructuring pattern into its own scope, separate from the `catch` body. Here's an example of code that was affected by this edge case: ```js // Original code let foo = 1 try { throw ['a', 'b'] } catch ({ [foo]: y }) { let foo = 2 assert(y === 'b') } // Old output (with --minify) let foo=1;try{throw["a","b"]}catch({[o]:t}){let o=2;assert(t==="b")} // New output (with --minify) let foo=1;try{throw["a","b"]}catch({[foo]:t}){let o=2;assert(t==="b")} ``` * Go 1.17.2 was upgraded to Go 1.17.4 The previous release was built with Go 1.17.2, but this release is built with Go 1.17.4. This is just a routine upgrade. There are no changes significant to esbuild outside of some security-related fixes to Go's HTTP stack (but you shouldn't be running esbuild's dev server in production anyway). One notable change related to this is that esbuild's publishing script now ensures that git's state is free of uncommitted and/or untracked files before building. Previously this wasn't the case because publishing esbuild involved changing the version number, running the publishing script, and committing at the end, which meant that files were uncommitted during the build process. I also typically had some untracked test files in the same directory during publishing (which is harmless). This matters because there's an upcoming change in Go 1.18 where the Go compiler will include metadata about whether there are untracked files or not when doing a build: https://github.com/golang/go/issues/37475. Changing esbuild's publishing script should mean that when esbuild upgrades to Go 1.18, esbuild's binary executables will be marked as being built off of a specific commit without any modifications. This is important for reproducibility. Checking out a specific esbuild commit and building it should give a bitwise-identical binary executable to one that I published. But if this metadata indicated that there were untracked files during the published build, then the resulting executable would no longer be bitwise-identical. ## 0.14.1 * Fix `imports` in `package.json` ([#1807](https://github.com/evanw/esbuild/issues/1807)) This release contains a fix for the rarely-used [`imports` feature in `package.json` files](https://nodejs.org/api/packages.html#subpath-imports) that lets a package specify a custom remapping for import paths inside that package that start with `#`. Support for `imports` was added in version 0.13.9. However, the field was being incorrectly interpreted as relative to the importing file instead of to the `package.json` file, which caused an import failure when the importing file is in a subdirectory instead of being at the top level of the package. Import paths should now be interpreted as relative to the correct directory which should fix these path resolution failures. * Isolate implicit sibling scope lookup for `enum` and `namespace` The previous release implemented sibling namespaces in TypeScript, which introduces a new kind of scope lookup that doesn't exist in JavaScript. Exported members inside an `enum` or `namespace` block can be implicitly referenced in a sibling `enum` or `namespace` block just by using the name without using a property reference. However, this behavior appears to only work for `enum`-to-`enum` and `namespace`-to-`namespace` interactions. Even though sibling enums and namespaces with the same name can be merged together into the same underlying object, this implicit reference behavior doesn't work for `enum`-to-`namespace` interactions and attempting to do this with a `namespace`-to-`enum` interaction [causes the TypeScript compiler itself to crash](https://github.com/microsoft/TypeScript/issues/46891). Here is an example of how the TypeScript compiler behaves in each case: ```ts // "b" is accessible enum a { b = 1 } enum a { c = b } // "e" is accessible namespace d { export let e = 1 } namespace d { export let f = e } // "h" is inaccessible enum g { h = 1 } namespace g { export let i = h } // This causes the TypeScript compiler to crash namespace j { export let k = 1 } enum j { l = k } ``` This release changes the implicit sibling scope lookup behavior to only work for `enum`-to-`enum` and `namespace`-to-`namespace` interactions. These implicit references no longer work with `enum`-to-`namespace` and `namespace`-to-`enum` interactions, which should more accurately match the behavior of the TypeScript compiler. * Add semicolon insertion before TypeScript-specific definite assignment assertion modifier ([#1810](https://github.com/evanw/esbuild/issues/1810)) TypeScript lets you add a `!` after a variable declaration to bypass TypeScript's definite assignment analysis: ```ts let x!: number[]; initialize(); x.push(4); function initialize() { x = [0, 1, 2, 3]; } ``` This `!` is called a [definite assignment assertion](https://devblogs.microsoft.com/typescript/announcing-typescript-2-7/#definite-assignment-assertions) and tells TypeScript to assume that the variable has been initialized somehow. However, JavaScript's automatic semicolon insertion rules should be able to insert a semicolon before it: ```ts let a !function(){}() ``` Previously the above code was incorrectly considered a syntax error in TypeScript. With this release, this code is now parsed correctly. * Log output to stderr has been overhauled This release changes the way log messages are formatted to stderr. The changes make the kind of message (e.g. error vs. warning vs. note) more obvious, and they also give more room for paragraph-style notes that can provide more detail about the message. Here's an example: Before: ``` > example.tsx:14:25: warning: Comparison with -0 using the "===" operator will also match 0 14 │ case 1: return x === -0 ╵ ~~ > example.tsx:21:23: error: Could not resolve "path" (use "--platform=node" when building for node) 21 │ const path = require('path') ╵ ~~~~~~ ``` After: ``` ▲ [WARNING] Comparison with -0 using the "===" operator will also match 0 example.tsx:14:25: 14 │ case 1: return x === -0 ╵ ~~ Floating-point equality is defined such that 0 and -0 are equal, so "x === -0" returns true for both 0 and -0. You need to use "Object.is(x, -0)" instead to test for -0. ✘ [ERROR] Could not resolve "path" example.tsx:21:23: 21 │ const path = require('path') ╵ ~~~~~~ The package "path" wasn't found on the file system but is built into node. Are you trying to bundle for node? You can use "--platform=node" to do that, which will remove this error. ``` Note that esbuild's formatted log output is for humans, not for machines. If you need to output a stable machine-readable format, you should be using the API for that. Build and transform results have arrays called `errors` and `warnings` with objects that represent the log messages. * Show inlined enum value names in comments When esbuild inlines an enum, it will now put a comment next to it with the original enum name: ```ts // Original code const enum Foo { FOO } console.log(Foo.FOO) // Old output console.log(0); // New output console.log(0 /* FOO */); ``` This matches the behavior of the TypeScript compiler, and should help with debugging. These comments are not generated if minification is enabled. ## 0.14.0 **This release contains backwards-incompatible changes.** Since esbuild is before version 1.0.0, these changes have been released as a new minor version to reflect this (as [recommended by npm](https://docs.npmjs.com/cli/v6/using-npm/semver/)). You should either be pinning the exact version of `esbuild` in your `package.json` file or be using a version range syntax that only accepts patch upgrades such as `~0.13.0`. See the documentation about [semver](https://docs.npmjs.com/cli/v6/using-npm/semver/) for more information. * Add support for TypeScript's `preserveValueImports` setting ([#1525](https://github.com/evanw/esbuild/issues/1525)) TypeScript 4.5, which was just released, added [a new setting called `preserveValueImports`](https://devblogs.microsoft.com/typescript/announcing-typescript-4-5/#preserve-value-imports). This release of esbuild implements support for this new setting. However, this release also changes esbuild's behavior regarding the `importsNotUsedAsValues` setting, so this release is being considered a breaking change. Now esbuild's behavior should more accurately match the behavior of the TypeScript compiler. This is described in more detail below. The difference in behavior is around unused imports. By default, unused import names are considered to be types and are completely removed if they are unused. If all import names are removed for a given import statement, then the whole import statement is removed too. The two `tsconfig.json` settings [`importsNotUsedAsValues`](https://www.typescriptlang.org/tsconfig#importsNotUsedAsValues) and [`preserveValueImports`](https://www.typescriptlang.org/tsconfig#preserveValueImports) let you customize this. Here's what the TypeScript compiler's output looks like with these different settings enabled: ```ts // Original code import { unused } from "foo"; // Default output /* (the import is completely removed) */ // Output with "importsNotUsedAsValues": "preserve" import "foo"; // Output with "preserveValueImports": true import { unused } from "foo"; ``` Previously, since the `preserveValueImports` setting didn't exist yet, esbuild had treated the `importsNotUsedAsValues` setting as if it were what is now the `preserveValueImports` setting instead. This was a deliberate deviation from how the TypeScript compiler behaves, but was necessary to allow esbuild to be used as a TypeScript-to-JavaScript compiler inside of certain composite languages such as Svelte and Vue. These languages append additional code after converting the TypeScript to JavaScript so unused imports may actually turn out to be used later on: ```svelte ``` Previously the implementers of these languages had to use the `importsNotUsedAsValues` setting as a hack for esbuild to preserve the import statements. With this release, esbuild now follows the behavior of the TypeScript compiler so implementers will need to use the new `preserveValueImports` setting to do this instead. This is the breaking change. * TypeScript code follows JavaScript class field semantics with `--target=esnext` ([#1480](https://github.com/evanw/esbuild/issues/1480)) TypeScript 4.3 included a subtle breaking change that wasn't mentioned in the [TypeScript 4.3 blog post](https://devblogs.microsoft.com/typescript/announcing-typescript-4-3/): class fields will now be compiled with different semantics if `"target": "ESNext"` is present in `tsconfig.json`. Specifically in this case `useDefineForClassFields` will default to `true` when not specified instead of `false`. This means class field behavior in TypeScript code will now match JavaScript instead of doing something else: ```js class Base { set foo(value) { console.log('set', value) } } class Derived extends Base { foo = 123 } new Derived() ``` In TypeScript 4.2 and below, the TypeScript compiler would generate code that prints `set 123` when `tsconfig.json` contains `"target": "ESNext"` but in TypeScript 4.3 and above, the TypeScript compiler will now generate code that doesn't print anything. This is the difference between "assign" semantics and "define" semantics. Previously you had to create a `tsconfig.json` file and specify `"target": "ESNext"` to get this behavior in esbuild. With this release, you can now also just pass `--target=esnext` to esbuild to force-enable this behavior. Note that esbuild doesn't do this by default even though the default value of `--target=` otherwise behaves like `esnext`. Since TypeScript's compiler doesn't do this behavior by default, it seems like a good idea for esbuild to not do this behavior by default either. In addition to the breaking changes above, the following changes are also included in this release: * Allow certain keywords as tuple type labels in TypeScript ([#1797](https://github.com/evanw/esbuild/issues/1797)) Apparently TypeScript lets you use certain keywords as tuple labels but not others. For example, `type x = [function: number]` is allowed while `type x = [class: number]` isn't. This release replicates this behavior in esbuild's TypeScript parser: * Allowed keywords: `false`, `function`, `import`, `new`, `null`, `this`, `true`, `typeof`, `void` * Forbidden keywords: `break`, `case`, `catch`, `class`, `const`, `continue`, `debugger`, `default`, `delete`, `do`, `else`, `enum`, `export`, `extends`, `finally`, `for`, `if`, `in`, `instanceof`, `return`, `super`, `switch`, `throw`, `try`, `var`, `while`, `with` * Support sibling namespaces in TypeScript ([#1410](https://github.com/evanw/esbuild/issues/1410)) TypeScript has a feature where sibling namespaces with the same name can implicitly reference each other's exports without an explicit property access. This goes against how scope lookup works in JavaScript, so it previously didn't work with esbuild. This release adds support for this feature: ```ts // Original TypeScript code namespace x { export let y = 123 } namespace x { export let z = y } // Old JavaScript output var x; (function(x2) { x2.y = 123; })(x || (x = {})); (function(x2) { x2.z = y; })(x || (x = {})); // New JavaScript output var x; (function(x2) { x2.y = 123; })(x || (x = {})); (function(x2) { x2.z = x2.y; })(x || (x = {})); ``` Notice how the identifier `y` is now compiled to the property access `x2.y` which references the export named `y` on the namespace, instead of being left as the identifier `y` which references the global named `y`. This matches how the TypeScript compiler treats namespace objects. This new behavior also works for enums: ```ts // Original TypeScript code enum x { y = 123 } enum x { z = y + 1 } // Old JavaScript output var x; (function(x2) { x2[x2["y"] = 123] = "y"; })(x || (x = {})); (function(x2) { x2[x2["z"] = y + 1] = "z"; })(x || (x = {})); // New JavaScript output var x; (function(x2) { x2[x2["y"] = 123] = "y"; })(x || (x = {})); (function(x2) { x2[x2["z"] = 124] = "z"; })(x || (x = {})); ``` Note that this behavior does **not** work across files. Each file is still compiled independently so the namespaces in each file are still resolved independently per-file. Implicit namespace cross-references still do not work across files. Getting this to work is counter to esbuild's parallel architecture and does not fit in with esbuild's design. It also doesn't make sense with esbuild's bundling model where input files are either in ESM or CommonJS format and therefore each have their own scope. * Change output for top-level TypeScript enums The output format for top-level TypeScript enums has been changed to reduce code size and improve tree shaking, which means that esbuild's enum output is now somewhat different than TypeScript's enum output. The behavior of both output formats should still be equivalent though. Here's an example that shows the difference: ```ts // Original code enum x { y = 1, z = 2 } // Old output var x; (function(x2) { x2[x2["y"] = 1] = "y"; x2[x2["z"] = 2] = "z"; })(x || (x = {})); // New output var x = /* @__PURE__ */ ((x2) => { x2[x2["y"] = 1] = "y"; x2[x2["z"] = 2] = "z"; return x2; })(x || {}); ``` The function expression has been changed to an arrow expression to reduce code size and the enum initializer has been moved into the variable declaration to make it possible to be marked as `/* @__PURE__ */` to improve tree shaking. The `/* @__PURE__ */` annotation is now automatically added when all of the enum values are side-effect free, which means the entire enum definition can be removed as dead code if it's never referenced. Direct enum value references within the same file that have been inlined do not count as references to the enum definition so this should eliminate enums from the output in many cases: ```ts // Original code enum Foo { FOO = 1 } enum Bar { BAR = 2 } console.log(Foo, Bar.BAR) // Old output (with --bundle --minify) var n;(function(e){e[e.FOO=1]="FOO"})(n||(n={}));var l;(function(e){e[e.BAR=2]="BAR"})(l||(l={}));console.log(n,2); // New output (with --bundle --minify) var n=(e=>(e[e.FOO=1]="FOO",e))(n||{});console.log(n,2); ``` Notice how the new output is much shorter because the entire definition for `Bar` has been completely removed as dead code by esbuild's tree shaking. The output may seem strange since it would be simpler to just have a plain object literal as an initializer. However, TypeScript's enum feature behaves similarly to TypeScript's namespace feature which means enums can merge with existing enums and/or existing namespaces (and in some cases also existing objects) if the existing definition has the same name. This new output format keeps its similarity to the original output format so that it still handles all of the various edge cases that TypeScript's enum feature supports. Initializing the enum using a plain object literal would not merge with existing definitions and would break TypeScript's enum semantics. * Fix legal comment parsing in CSS ([#1796](https://github.com/evanw/esbuild/issues/1796)) Legal comments in CSS either start with `/*!` or contain `@preserve` or `@license` and are preserved by esbuild in the generated CSS output. This release fixes a bug where non-top-level legal comments inside a CSS file caused esbuild to skip any following legal comments even if those following comments are top-level: ```css /* Original code */ .example { --some-var: var(--tw-empty, /*!*/ /*!*/); } /*! Some legal comment */ body { background-color: red; } /* Old output (with --minify) */ .example{--some-var: var(--tw-empty, )}body{background-color:red} /* New output (with --minify) */ .example{--some-var: var(--tw-empty, )}/*! Some legal comment */body{background-color:red} ``` * Fix panic when printing invalid CSS ([#1803](https://github.com/evanw/esbuild/issues/1803)) This release fixes a panic caused by a conditional CSS `@import` rule with a URL token. Code like this caused esbuild to enter an unexpected state because the case where tokens in the import condition with associated import records wasn't handled. This case is now handled correctly: ```css @import "example.css" url(foo); ``` * Mark `Set` and `Map` with array arguments as pure ([#1791](https://github.com/evanw/esbuild/issues/1791)) This release introduces special behavior for references to the global `Set` and `Map` constructors that marks them as `/* @__PURE__ */` if they are known to not have any side effects. These constructors evaluate the iterator of whatever is passed to them and the iterator could have side effects, so this is only safe if whatever is passed to them is an array, since the array iterator has no side effects. Marking a constructor call as `/* @__PURE__ */` means it's safe to remove if the result is unused. This is an existing feature that you can trigger by manually adding a `/* @__PURE__ */` comment before a constructor call. The difference is that this release contains special behavior to automatically mark `Set` and `Map` as pure for you as long as it's safe to do so. As with all constructor calls that are marked `/* @__PURE__ */`, any internal expressions which could cause side effects are still preserved even though the constructor call itself is removed: ```js // Original code new Map([ ['a', b()], [c(), new Set(['d', e()])], ]); // Old output (with --minify) new Map([["a",b()],[c(),new Set(["d",e()])]]); // New output (with --minify) b(),c(),e(); ``` ## 0.13.15 * Fix `super` in lowered `async` arrow functions ([#1777](https://github.com/evanw/esbuild/issues/1777)) This release fixes an edge case that was missed when lowering `async` arrow functions containing `super` property accesses for compile targets that don't support `async` such as with `--target=es6`. The problem was that lowering transforms `async` arrow functions into generator function expressions that are then passed to an esbuild helper function called `__async` that implements the `async` state machine behavior. Since function expressions do not capture `this` and `super` like arrow functions do, this led to a mismatch in behavior which meant that the transform was incorrect. The fix is to introduce a helper function to forward `super` access into the generator function expression body. Here's an example: ```js // Original code class Foo extends Bar { foo() { return async () => super.bar() } } // Old output (with --target=es6) class Foo extends Bar { foo() { return () => __async(this, null, function* () { return super.bar(); }); } } // New output (with --target=es6) class Foo extends Bar { foo() { return () => { var __superGet = (key) => super[key]; return __async(this, null, function* () { return __superGet("bar").call(this); }); }; } } ``` * Avoid merging certain CSS rules with different units ([#1732](https://github.com/evanw/esbuild/issues/1732)) This release no longer collapses `border-radius`, `margin`, `padding`, and `inset` rules when they have units with different levels of browser support. Collapsing multiple of these rules into a single rule is not equivalent if the browser supports one unit but not the other unit, since one rule would still have applied before the collapse but no longer applies after the collapse due to the whole rule being ignored. For example, Chrome 10 supports the `rem` unit but not the `vw` unit, so the CSS code below should render with rounded corners in Chrome 10. However, esbuild previously merged everything into a single rule which would cause Chrome 10 to ignore the rule and not round the corners. This issue is now fixed: ```css /* Original CSS */ div { border-radius: 1rem; border-top-left-radius: 1vw; margin: 0; margin-top: 1Q; left: 10Q; top: 20Q; right: 10Q; bottom: 20Q; } /* Old output (with --minify) */ div{border-radius:1vw 1rem 1rem;margin:1Q 0 0;inset:20Q 10Q} /* New output (with --minify) */ div{border-radius:1rem;border-top-left-radius:1vw;margin:0;margin-top:1Q;inset:20Q 10Q} ``` Notice how esbuild can still collapse rules together when they all share the same unit, even if the unit is one that doesn't have universal browser support such as the unit `Q`. One subtlety is that esbuild now distinguishes between "safe" and "unsafe" units where safe units are old enough that they are guaranteed to work in any browser a user might reasonably use, such as `px`. Safe units are allowed to be collapsed together even if there are multiple different units while multiple different unsafe units are not allowed to be collapsed together. Another detail is that esbuild no longer minifies zero lengths by removing the unit if the unit is unsafe (e.g. `0rem` into `0`) since that could cause a rendering difference if a previously-ignored rule is now no longer ignored due to the unit change. If you are curious, you can learn more about browser support levels for different CSS units in [Mozilla's documentation about CSS length units](https://developer.mozilla.org/en-US/docs/Web/CSS/length). * Avoid warning about ignored side-effect free imports for empty files ([#1785](https://github.com/evanw/esbuild/issues/1785)) When bundling, esbuild warns about bare imports such as `import "lodash-es"` when the package has been marked as `"sideEffects": false` in its `package.json` file. This is because the only reason to use a bare import is because you are relying on the side effects of the import, but imports for packages marked as side-effect free are supposed to be removed. If the package indicates that it has no side effects, then this bare import is likely a bug. However, some people have packages just for TypeScript type definitions. These package can actually have a side effect as they can augment the type of the global object in TypeScript, even if they are marked with `"sideEffects": false`. To avoid warning in this case, esbuild will now only issue this warning if the imported file is non-empty. If the file is empty, then it's irrelevant whether you import it or not so any import of that file does not indicate a bug. This fixes this case because `.d.ts` files typically end up being empty after esbuild parses them since they typically only contain type declarations. * Attempt to fix packages broken due to the `node:` prefix ([#1760](https://github.com/evanw/esbuild/issues/1760)) Some people have started using the node-specific `node:` path prefix in their packages. This prefix forces the following path to be interpreted as a node built-in module instead of a package on the file system. So `require("node:path")` will always import [node's `path` module](https://nodejs.org/api/path.html) and never import [npm's `path` package](https://www.npmjs.com/package/path). Adding the `node:` prefix breaks that code with older node versions that don't understand the `node:` prefix. This is a problem with the package, not with esbuild. The package should be adding a fallback if the `node:` prefix isn't available. However, people still want to be able to use these packages with older node versions even though the code is broken. Now esbuild will automatically strip this prefix if it detects that the code will break in the configured target environment (as specified by `--target=`). Note that this only happens during bundling, since import paths are only examined during bundling. ## 0.13.14 * Fix dynamic `import()` on node 12.20+ ([#1772](https://github.com/evanw/esbuild/issues/1772)) When you use flags such as `--target=node12.20`, esbuild uses that version number to see what features the target environment supports. This consults an internal table that stores which target environments are supported for each feature. For example, `import(x)` is changed into `Promise.resolve().then(() => require(x))` if dynamic `import` expressions are unsupported. Previously esbuild's internal table only stored one version number, since features are rarely ever removed in newer versions of software. Either the target environment is before that version and the feature is unsupported, or the target environment is after that version and the feature is supported. This approach has work for all relevant features in all cases except for one: dynamic `import` support in node. This feature is supported in node 12.20.0 up to but not including node 13.0.0, and then is also supported in node 13.2.0 up. The feature table implementation has been changed to store an array of potentially discontiguous version ranges instead of one version number. Up until now, esbuild used 13.2.0 as the lowest supported version number to avoid generating dynamic `import` expressions when targeting node versions that don't support it. But with this release, esbuild will now use the more accurate discontiguous version range in this case. This means dynamic `import` expressions can now be generated when targeting versions of node 12.20.0 up to but not including node 13.0.0. * Avoid merging certain qualified rules in CSS ([#1776](https://github.com/evanw/esbuild/issues/1776)) A change was introduced in the previous release to merge adjacent CSS rules that have the same content: ```css /* Original code */ a { color: red } b { color: red } /* Minified output */ a,b{color:red} ``` However, that introduced a regression in cases where the browser considers one selector to be valid and the other selector to be invalid, such as in the following example: ```css /* This rule is valid, and is applied */ a { color: red } /* This rule is invalid, and is ignored */ b:-x-invalid { color: red } ``` Merging these two rules into one causes the browser to consider the entire merged rule to be invalid, which disables both rules. This is a change in behavior from the original code. With this release, esbuild will now only merge adjacent duplicate rules together if they are known to work in all browsers (specifically, if they are known to work in IE 7 and up). Adjacent duplicate rules will no longer be merged in all other cases including modern pseudo-class selectors such as `:focus`, HTML5 elements such as `video`, and combinators such as `a + b`. * Minify syntax in the CSS `font`, `font-family`, and `font-weight` properties ([#1756](https://github.com/evanw/esbuild/pull/1756)) This release includes size reductions for CSS font syntax when minification is enabled: ```css /* Original code */ div { font: bold 1rem / 1.2 "Segoe UI", sans-serif, "Segoe UI Emoji"; } /* Output with "--minify" */ div{font:700 1rem/1.2 Segoe UI,sans-serif,"Segoe UI Emoji"} ``` Notice how `bold` has been changed to `700` and the quotes were removed around `"Segoe UI"` since it was safe to do so. This feature was contributed by [@sapphi-red](https://github.com/sapphi-red). ## 0.13.13 * Add more information about skipping `"main"` in `package.json` ([#1754](https://github.com/evanw/esbuild/issues/1754)) Configuring `mainFields: []` breaks most npm packages since it tells esbuild to ignore the `"main"` field in `package.json`, which most npm packages use to specify their entry point. This is not a bug with esbuild because esbuild is just doing what it was told to do. However, people may do this without understanding how npm packages work, and then be confused about why it doesn't work. This release now includes additional information in the error message: ``` > foo.js:1:27: error: Could not resolve "events" (use "--platform=node" when building for node) 1 │ var EventEmitter = require('events') ╵ ~~~~~~~~ node_modules/events/package.json:20:2: note: The "main" field was ignored because the list of main fields to use is currently set to [] 20 │ "main": "./events.js", ╵ ~~~~~~ ``` * Fix a tree-shaking bug with `var exports` ([#1739](https://github.com/evanw/esbuild/issues/1739)) This release fixes a bug where a variable named `var exports = {}` was incorrectly removed by tree-shaking (i.e. dead code elimination). The `exports` variable is a special variable in CommonJS modules that is automatically provided by the CommonJS runtime. CommonJS modules are transformed into something like this before being run: ```js function(exports, module, require) { var exports = {} } ``` So using `var exports = {}` should have the same effect as `exports = {}` because the variable `exports` should already be defined. However, esbuild was incorrectly overwriting the definition of the `exports` variable with the one provided by CommonJS. This release merges the definitions together so both are included, which fixes the bug. * Merge adjacent CSS selector rules with duplicate content ([#1755](https://github.com/evanw/esbuild/issues/1755)) With this release, esbuild will now merge adjacent selectors when minifying if they have the same content: ```css /* Original code */ a { color: red } b { color: red } /* Old output (with --minify) */ a{color:red}b{color:red} /* New output (with --minify) */ a,b{color:red} ``` * Shorten `top`, `right`, `bottom`, `left` CSS property into `inset` when it is supported ([#1758](https://github.com/evanw/esbuild/pull/1758)) This release enables collapsing of `inset` related properties: ```css /* Original code */ div { top: 0; right: 0; bottom: 0; left: 0; } /* Output with "--minify-syntax" */ div { inset: 0; } ``` This minification rule is only enabled when `inset` property is supported by the target environment. Make sure to set esbuild's `target` setting correctly when minifying if the code will be running in an older environment (e.g. earlier than Chrome 87). This feature was contributed by [@sapphi-red](https://github.com/sapphi-red). ## 0.13.12 * Implement initial support for simplifying `calc()` expressions in CSS ([#1607](https://github.com/evanw/esbuild/issues/1607)) This release includes basic simplification of `calc()` expressions in CSS when minification is enabled. The approach mainly follows the official CSS specification, which means it should behave the way browsers behave: https://www.w3.org/TR/css-values-4/#calc-func. This is a basic implementation so there are probably some `calc()` expressions that can be reduced by other tools but not by esbuild. This release mainly focuses on setting up the parsing infrastructure for `calc()` expressions to make it straightforward to implement additional simplifications in the future. Here's an example of this new functionality: ```css /* Input CSS */ div { width: calc(60px * 4 - 5px * 2); height: calc(100% / 4); } /* Output CSS (with --minify-syntax) */ div { width: 230px; height: 25%; } ``` Expressions that can't be fully simplified will still be partially simplified into a reduced `calc()` expression: ```css /* Input CSS */ div { width: calc(100% / 5 - 2 * 1em - 2 * 1px); } /* Output CSS (with --minify-syntax) */ div { width: calc(20% - 2em - 2px); } ``` Note that this transformation doesn't attempt to modify any expression containing a `var()` CSS variable reference. These variable references can contain any number of tokens so it's not safe to move forward with a simplification assuming that `var()` is a single token. For example, `calc(2px * var(--x) * 3)` is not transformed into `calc(6px * var(--x))` in case `var(--x)` contains something like `4 + 5px` (`calc(2px * 4 + 5px * 3)` evaluates to `23px` while `calc(6px * 4 + 5px)` evaluates to `29px`). * Fix a crash with a legal comment followed by an import ([#1730](https://github.com/evanw/esbuild/issues/1730)) Version 0.13.10 introduced parsing for CSS legal comments but caused a regression in the code that checks whether there are any rules that come before `@import`. This is not desired because browsers ignore `@import` rules after other non-`@import` rules, so esbuild warns you when you do this. However, legal comments are modeled as rules in esbuild's internal AST even though they aren't actual CSS rules, and the code that performs this check wasn't updated. This release fixes the crash. ## 0.13.11 * Implement class static blocks ([#1558](https://github.com/evanw/esbuild/issues/1558)) This release adds support for a new upcoming JavaScript feature called [class static blocks](https://github.com/tc39/proposal-class-static-block) that lets you evaluate code inside of a class body. It looks like this: ```js class Foo { static { this.foo = 123 } } ``` This can be useful when you want to use `try`/`catch` or access private `#name` fields during class initialization. Doing that without this feature is quite hacky and basically involves creating temporary static fields containing immediately-invoked functions and then deleting the fields after class initialization. Static blocks are much more ergonomic and avoid performance loss due to `delete` changing the object shape. Static blocks are transformed for older browsers by moving the static block outside of the class body and into an immediately invoked arrow function after the class definition: ```js // The transformed version of the example code above const _Foo = class { }; let Foo = _Foo; (() => { _Foo.foo = 123; })(); ``` In case you're wondering, the additional `let` variable is to guard against the potential reassignment of `Foo` during evaluation such as what happens below. The value of `this` must be bound to the original class, not to the current value of `Foo`: ```js let bar class Foo { static { bar = () => this } } Foo = null console.log(bar()) // This should not be "null" ``` * Fix issues with `super` property accesses Code containing `super` property accesses may need to be transformed even when they are supported. For example, in ES6 `async` methods are unsupported while `super` properties are supported. An `async` method containing `super` property accesses requires those uses of `super` to be transformed (the `async` function is transformed into a nested generator function and the `super` keyword cannot be used inside nested functions). Previously esbuild transformed `super` property accesses into a function call that returned the corresponding property. However, this was incorrect for uses of `super` that write to the inherited setter since a function call is not a valid assignment target. This release fixes writing to a `super` property: ```js // Original code class Base { set foo(x) { console.log('set foo to', x) } } class Derived extends Base { async bar() { super.foo = 123 } } new Derived().bar() // Old output with --target=es6 (contains a syntax error) class Base { set foo(x) { console.log("set foo to", x); } } class Derived extends Base { bar() { var __super = (key) => super[key]; return __async(this, null, function* () { __super("foo") = 123; }); } } new Derived().bar(); // New output with --target=es6 (works correctly) class Base { set foo(x) { console.log("set foo to", x); } } class Derived extends Base { bar() { var __superSet = (key, value) => super[key] = value; return __async(this, null, function* () { __superSet("foo", 123); }); } } new Derived().bar(); ``` All known edge cases for assignment to a `super` property should now be covered including destructuring assignment and using the unary assignment operators with BigInts. In addition, this release also fixes a bug where a `static` class field containing a `super` property access was not transformed when it was moved outside of the class body, which can happen when `static` class fields aren't supported. ```js // Original code class Base { static get foo() { return 123 } } class Derived extends Base { static bar = super.foo } // Old output with --target=es6 (contains a syntax error) class Base { static get foo() { return 123; } } class Derived extends Base { } __publicField(Derived, "bar", super.foo); // New output with --target=es6 (works correctly) class Base { static get foo() { return 123; } } const _Derived = class extends Base { }; let Derived = _Derived; __publicField(Derived, "bar", __superStaticGet(_Derived, "foo")); ``` All known edge cases for `super` inside `static` class fields should be handled including accessing `super` after prototype reassignment of the enclosing class object. ## 0.13.10 * Implement legal comment preservation for CSS ([#1539](https://github.com/evanw/esbuild/issues/1539)) This release adds support for legal comments in CSS the same way they are already supported for JS. A legal comment is one that starts with `/*!` or that contains the text `@license` or `@preserve`. These comments are preserved in output files by esbuild since that follows the intent of the original authors of the code. The specific behavior is controlled via `--legal-comments=` in the CLI and `legalComments` in the JS API, which can be set to any of the following options: * `none`: Do not preserve any legal comments * `inline`: Preserve all rule-level legal comments * `eof`: Move all rule-level legal comments to the end of the file * `linked`: Move all rule-level legal comments to a `.LEGAL.txt` file and link to them with a comment * `external`: Move all rule-level legal comments to a `.LEGAL.txt` file but to not link to them The default behavior is `eof` when bundling and `inline` otherwise. * Allow uppercase `es*` targets ([#1717](https://github.com/evanw/esbuild/issues/1717)) With this release, you can now use target names such as `ESNext` instead of `esnext` as the target name in the CLI and JS API. This is important because people don't want to have to call `.toLowerCase()` on target strings from TypeScript's `tsconfig.json` file before passing it to esbuild (TypeScript uses case-agnostic target names). This feature was contributed by [@timse](https://github.com/timse). * Update to Unicode 14.0.0 The character tables that determine which characters form valid JavaScript identifiers have been updated from Unicode version 13.0.0 to the newly release Unicode version 14.0.0. I'm not putting an example in the release notes because all of the new characters will likely just show up as little squares since fonts haven't been updated yet. But you can read https://www.unicode.org/versions/Unicode14.0.0/#Summary for more information about the changes. ## 0.13.9 * Add support for `imports` in `package.json` ([#1691](https://github.com/evanw/esbuild/issues/1691)) This release adds basic support for the `imports` field in `package.json`. It behaves similarly to the `exports` field but only applies to import paths that start with `#`. The `imports` field provides a way for a package to remap its own internal imports for itself, while the `exports` field provides a way for a package to remap its external exports for other packages. This is useful because the `imports` field respects the currently-configured conditions which means that the import mapping can change at run-time. For example: ``` $ cat entry.mjs import '#example' $ cat package.json { "imports": { "#example": { "foo": "./example.foo.mjs", "default": "./example.mjs" } } } $ cat example.foo.mjs console.log('foo is enabled') $ cat example.mjs console.log('foo is disabled') $ node entry.mjs foo is disabled $ node --conditions=foo entry.mjs foo is enabled ``` Now that esbuild supports this feature too, import paths starting with `#` and any provided conditions will be respected when bundling: ``` $ esbuild --bundle entry.mjs | node foo is disabled $ esbuild --conditions=foo --bundle entry.mjs | node foo is enabled ``` * Fix using `npm rebuild` with the `esbuild` package ([#1703](https://github.com/evanw/esbuild/issues/1703)) Version 0.13.4 accidentally introduced a regression in the install script where running `npm rebuild` multiple times could fail after the second time. The install script creates a copy of the binary executable using [`link`](https://man7.org/linux/man-pages/man2/link.2.html) followed by [`rename`](https://www.man7.org/linux/man-pages/man2/rename.2.html). Using `link` creates a hard link which saves space on the file system, and `rename` is used for safety since it atomically replaces the destination. However, the `rename` syscall has an edge case where it silently fails if the source and destination are both the same link. This meant that the install script would fail after being run twice in a row. With this release, the install script now deletes the source after calling `rename` in case it has silently failed, so this issue should now be fixed. It should now be safe to use `npm rebuild` with the `esbuild` package. * Fix invalid CSS minification of `border-radius` ([#1702](https://github.com/evanw/esbuild/issues/1702)) CSS minification does collapsing of `border-radius` related properties. For example: ```css /* Original CSS */ div { border-radius: 1px; border-top-left-radius: 5px; } /* Minified CSS */ div{border-radius:5px 1px 1px} ``` However, this only works for numeric tokens, not identifiers. For example: ```css /* Original CSS */ div { border-radius: 1px; border-top-left-radius: inherit; } /* Minified CSS */ div{border-radius:1px;border-top-left-radius:inherit} ``` Transforming this to `div{border-radius:inherit 1px 1px}`, as was done in previous releases of esbuild, is an invalid transformation and results in incorrect CSS. This release of esbuild fixes this CSS transformation bug. ## 0.13.8 * Fix `super` inside arrow function inside lowered `async` function ([#1425](https://github.com/evanw/esbuild/issues/1425)) When an `async` function is transformed into a regular function for target environments that don't support `async` such as `--target=es6`, references to `super` inside that function must be transformed too since the `async`-to-regular function transformation moves the function body into a nested function, so the `super` references are no longer syntactically valid. However, this transform didn't handle an edge case and `super` references inside of an arrow function were overlooked. This release fixes this bug: ```js // Original code class Foo extends Bar { async foo() { return () => super.foo() } } // Old output (with --target=es6) class Foo extends Bar { foo() { return __async(this, null, function* () { return () => super.foo(); }); } } // New output (with --target=es6) class Foo extends Bar { foo() { var __super = (key) => super[key]; return __async(this, null, function* () { return () => __super("foo").call(this); }); } } ``` * Remove the implicit `/` after `[dir]` in entry names ([#1661](https://github.com/evanw/esbuild/issues/1661)) The "entry names" feature lets you customize the way output file names are generated. The `[dir]` and `[name]` placeholders are filled in with the directory name and file name of the corresponding entry point file, respectively. Previously `--entry-names=[dir]/[name]` and `--entry-names=[dir][name]` behaved the same because the value used for `[dir]` always had an implicit trailing slash, since it represents a directory. However, some people want to be able to remove the file name with `--entry-names=[dir]` and the implicit trailing slash gets in the way. With this release, you can now use the `[dir]` placeholder without an implicit trailing slash getting in the way. For example, the command `esbuild foo/bar/index.js --outbase=. --outdir=out --entry-names=[dir]` previously generated the file `out/foo/bar/.js` but will now generate the file `out/foo/bar.js`. ## 0.13.7 * Minify CSS alpha values correctly ([#1682](https://github.com/evanw/esbuild/issues/1682)) When esbuild uses the `rgba()` syntax for a color instead of the 8-character hex code (e.g. when `target` is set to Chrome 61 or earlier), the 0-to-255 integer alpha value must be printed as a floating-point fraction between 0 and 1. The fraction was only printed to three decimal places since that is the minimal number of decimal places required for all 256 different alpha values to be uniquely determined. However, using three decimal places does not necessarily result in the shortest result. For example, `128 / 255` is `0.5019607843137255` which is printed as `".502"` using three decimal places, but `".5"` is equivalent because `round(0.5 * 255) == 128`, so printing `".5"` would be better. With this release, esbuild will always use the minimal numeric representation for the alpha value: ```css /* Original code */ a { color: #FF800080 } /* Old output (with --minify --target=chrome61) */ a{color:rgba(255,128,0,.502)} /* New output (with --minify --target=chrome61) */ a{color:rgba(255,128,0,.5)} ``` * Match node's behavior for core module detection ([#1680](https://github.com/evanw/esbuild/issues/1680)) Node has a hard-coded list of core modules (e.g. `fs`) that, when required, short-circuit the module resolution algorithm and instead return the corresponding internal core module object. When you pass `--platform=node` to esbuild, esbuild also implements this short-circuiting behavior and doesn't try to bundle these import paths. This was implemented in esbuild using the existing `external` feature (e.g. essentially `--external:fs`). However, there is an edge case where esbuild's `external` feature behaved differently than node. Modules specified via esbuild's `external` feature also cause all sub-paths to be excluded as well, so for example `--external:foo` excludes both `foo` and `foo/bar` from the bundle. However, node's core module check is only an exact equality check, so for example `fs` is a core module and bypasses the module resolution algorithm but `fs/foo` is not a core module and causes the module resolution algorithm to search the file system. This behavior can be used to load a module on the file system with the same name as one of node's core modules. For example, `require('fs/')` will load the module `fs` from the file system instead of loading node's core `fs` module. With this release, esbuild will now match node's behavior in this edge case. This means the external modules that are automatically added by `--platform=node` now behave subtly differently than `--external:`, which allows code that relies on this behavior to be bundled correctly. * Fix WebAssembly builds on Go 1.17.2+ ([#1684](https://github.com/evanw/esbuild/pull/1684)) Go 1.17.2 introduces a change (specifically a [fix for CVE-2021-38297](https://go-review.googlesource.com/c/go/+/354591/)) that causes Go's WebAssembly bootstrap script to throw an error when it's run in situations with many environment variables. One such situation is when the bootstrap script is run inside [GitHub Actions](https://github.com/features/actions). This change was introduced because the bootstrap script writes a copy of the environment variables into WebAssembly memory without any bounds checking, and writing more than 4096 bytes of data ends up writing past the end of the buffer and overwriting who-knows-what. So throwing an error in this situation is an improvement. However, this breaks esbuild which previously (at least seemingly) worked fine. With this release, esbuild's WebAssembly bootstrap script that calls out to Go's WebAssembly bootstrap script will now delete all environment variables except for the ones that esbuild checks for, of which there are currently only four: `NO_COLOR`, `NODE_PATH`, `npm_config_user_agent`, and `WT_SESSION`. This should avoid a crash when esbuild is built using Go 1.17.2+ and should reduce the likelihood of memory corruption when esbuild is built using Go 1.17.1 or earlier. This release also updates the Go version that esbuild ships with to version 1.17.2. Note that this problem only affects the `esbuild-wasm` package. The `esbuild` package is not affected. See also: * https://github.com/golang/go/issues/48797 * https://github.com/golang/go/issues/49011 ## 0.13.6 * Emit decorators for `declare` class fields ([#1675](https://github.com/evanw/esbuild/issues/1675)) In version 3.7, TypeScript introduced the `declare` keyword for class fields that avoids generating any code for that field: ```ts // TypeScript input class Foo { a: number declare b: number } // JavaScript output class Foo { a; } ``` However, it turns out that TypeScript still emits decorators for these omitted fields. With this release, esbuild will now do this too: ```ts // TypeScript input class Foo { @decorator a: number; @decorator declare b: number; } // Old JavaScript output class Foo { a; } __decorateClass([ decorator ], Foo.prototype, "a", 2); // New JavaScript output class Foo { a; } __decorateClass([ decorator ], Foo.prototype, "a", 2); __decorateClass([ decorator ], Foo.prototype, "b", 2); ``` * Experimental support for esbuild on NetBSD ([#1624](https://github.com/evanw/esbuild/pull/1624)) With this release, esbuild now has a published binary executable for [NetBSD](https://www.netbsd.org/) in the [`esbuild-netbsd-64`](https://www.npmjs.com/package/esbuild-netbsd-64) npm package, and esbuild's installer has been modified to attempt to use it when on NetBSD. Hopefully this makes installing esbuild via npm work on NetBSD. This change was contributed by [@gdt](https://github.com/gdt). ⚠️ Note: NetBSD is not one of [Node's supported platforms](https://nodejs.org/api/process.html#process_process_platform), so installing esbuild may or may not work on NetBSD depending on how Node has been patched. This is not a problem with esbuild. ⚠️ * Disable the "esbuild was bundled" warning if `ESBUILD_BINARY_PATH` is provided ([#1678](https://github.com/evanw/esbuild/pull/1678)) The `ESBUILD_BINARY_PATH` environment variable allows you to substitute an alternate binary executable for esbuild's JavaScript API. This is useful in certain cases such as when debugging esbuild. The JavaScript API has some code that throws an error if it detects that it was bundled before being run, since bundling prevents esbuild from being able to find the path to its binary executable. However, that error is unnecessary if `ESBUILD_BINARY_PATH` is present because an alternate path has been provided. This release disables the warning when `ESBUILD_BINARY_PATH` is present so that esbuild can be used when bundled as long as you also manually specify `ESBUILD_BINARY_PATH`. This change was contributed by [@heypiotr](https://github.com/heypiotr). * Remove unused `catch` bindings when minifying ([#1660](https://github.com/evanw/esbuild/pull/1660)) With this release, esbuild will now remove unused `catch` bindings when minifying: ```js // Original code try { throw 0; } catch (e) { } // Old output (with --minify) try{throw 0}catch(t){} // New output (with --minify) try{throw 0}catch{} ``` This takes advantage of the new [optional catch binding](https://github.com/tc39/proposal-optional-catch-binding) syntax feature that was introduced in ES2019. This minification rule is only enabled when optional catch bindings are supported by the target environment. Specifically, it's not enabled when using `--target=es2018` or older. Make sure to set esbuild's `target` setting correctly when minifying if the code will be running in an older JavaScript environment. This change was contributed by [@sapphi-red](https://github.com/sapphi-red). ## 0.13.5 * Improve watch mode accuracy ([#1113](https://github.com/evanw/esbuild/issues/1113)) Watch mode is enabled by `--watch` and causes esbuild to become a long-running process that automatically rebuilds output files when input files are changed. It's implemented by recording all calls to esbuild's internal file system interface and then invalidating the build whenever these calls would return different values. For example, a call to esbuild's internal `ReadFile()` function is considered to be different if either the presence of the file has changed (e.g. the file didn't exist before but now exists) or the presence of the file stayed the same but the content of the file has changed. Previously esbuild's watch mode operated at the `ReadFile()` and `ReadDirectory()` level. When esbuild checked whether a directory entry existed or not (e.g. whether a directory contains a `node_modules` subdirectory or a `package.json` file), it called `ReadDirectory()` which then caused the build to depend on that directory's set of entries. This meant the build would be invalidated even if a new unrelated entry was added or removed, since that still changes the set of entries. This is problematic when using esbuild in environments that constantly create and destroy temporary directory entries in your project directory. In that case, esbuild's watch mode would constantly rebuild as the directory was constantly considered to be dirty. With this release, watch mode now operates at the `ReadFile()` and `ReadDirectory().Get()` level. So when esbuild checks whether a directory entry exists or not, the build should now only depend on the presence status for that one directory entry. This should avoid unnecessary rebuilds due to unrelated directory entries being added or removed. The log messages generated using `--watch` will now also mention the specific directory entry whose presence status was changed if a build is invalidated for this reason. Note that this optimization does not apply to plugins using the `watchDirs` return value because those paths are only specified at the directory level and do not describe individual directory entries. You can use `watchFiles` or `watchDirs` on the individual entries inside the directory to get a similar effect instead. * Disallow certain uses of `<` in `.mts` and `.cts` files The upcoming version 4.5 of TypeScript is introducing the `.mts` and `.cts` extensions that turn into the `.mjs` and `.cjs` extensions when compiled. However, unlike the existing `.ts` and `.tsx` extensions, expressions that start with `<` are disallowed when they would be ambiguous depending on whether they are parsed in `.ts` or `.tsx` mode. The ambiguity is caused by the overlap between the syntax for JSX elements and the old deprecated syntax for type casts: | Syntax | `.ts` | `.tsx` | `.mts`/`.cts` | |-------------------------------|----------------------|------------------|----------------------| | `y` | ✅ Type cast | 🚫 Syntax error | 🚫 Syntax error | | `() => {}` | ✅ Arrow function | 🚫 Syntax error | 🚫 Syntax error | | `y` | 🚫 Syntax error | ✅ JSX element | 🚫 Syntax error | | `() => {}` | 🚫 Syntax error | ✅ JSX element | 🚫 Syntax error | | `() => {}` | 🚫 Syntax error | ✅ JSX element | 🚫 Syntax error | | `() => {}` | 🚫 Syntax error | ✅ JSX element | 🚫 Syntax error | | `() => {}` | ✅ Arrow function | ✅ Arrow function | ✅ Arrow function | | `() => {}` | ✅ Arrow function | ✅ Arrow function | ✅ Arrow function | This release of esbuild introduces a syntax error for these ambiguous syntax constructs in `.mts` and `.cts` files to match the new behavior of the TypeScript compiler. * Do not remove empty `@keyframes` rules ([#1665](https://github.com/evanw/esbuild/issues/1665)) CSS minification in esbuild automatically removes empty CSS rules, since they have no effect. However, empty `@keyframes` rules still trigger JavaScript animation events so it's incorrect to remove them. To demonstrate that empty `@keyframes` rules still have an effect, here is a bug report for Firefox where it was incorrectly not triggering JavaScript animation events for empty `@keyframes` rules: https://bugzilla.mozilla.org/show_bug.cgi?id=1004377. With this release, empty `@keyframes` rules are now preserved during minification: ```css /* Original CSS */ @keyframes foo { from {} to {} } /* Old output (with --minify) */ /* New output (with --minify) */ @keyframes foo{} ``` This fix was contributed by [@eelco](https://github.com/eelco). * Fix an incorrect duplicate label error ([#1671](https://github.com/evanw/esbuild/pull/1671)) When labeling a statement in JavaScript, the label must be unique within the enclosing statements since the label determines the jump target of any labeled `break` or `continue` statement: ```js // This code is valid x: y: z: break x; // This code is invalid x: y: x: break x; ``` However, an enclosing label with the same name *is* allowed as long as it's located in a different function body. Since `break` and `continue` statements can't jump across function boundaries, the label is not ambiguous. This release fixes a bug where esbuild incorrectly treated this valid code as a syntax error: ```js // This code is valid, but was incorrectly considered a syntax error x: (() => { x: break x; })(); ``` This fix was contributed by [@nevkontakte](https://github.com/nevkontakte). ## 0.13.4 * Fix permission issues with the install script ([#1642](https://github.com/evanw/esbuild/issues/1642)) The `esbuild` package contains a small JavaScript stub file that implements the CLI (command-line interface). Its only purpose is to spawn the binary esbuild executable as a child process and forward the command-line arguments to it. The install script contains an optimization that replaces this small JavaScript stub with the actual binary executable at install time to avoid the overhead of unnecessarily creating a new `node` process. This optimization can't be done at package publish time because there is only one `esbuild` package but there are many supported platforms, so the binary executable for the current platform must live outside of the `esbuild` package. However, the optimization was implemented with an [unlink](https://www.man7.org/linux/man-pages/man2/unlink.2.html) operation followed by a [link](https://www.man7.org/linux/man-pages/man2/link.2.html) operation. This means that if the first step fails, the package is left in a broken state since the JavaScript stub file is deleted but not yet replaced. With this release, the optimization is now implemented with a [link](https://www.man7.org/linux/man-pages/man2/link.2.html) operation followed by a [rename](https://www.man7.org/linux/man-pages/man2/rename.2.html) operation. This should always leave the package in a working state even if either step fails. * Add a fallback for `npm install esbuild --no-optional` ([#1647](https://github.com/evanw/esbuild/issues/1647)) The installation method for esbuild's platform-specific binary executable was recently changed in version 0.13.0. Before that version esbuild downloaded it in an install script, and after that version esbuild lets the package manager download it using the `optionalDependencies` feature in `package.json`. This change was made because downloading the binary executable in an install script never really fully worked. The reasons are complex but basically there are a variety of edge cases where people people want to install esbuild in environments that they have customized such that downloading esbuild isn't possible. Using `optionalDependencies` instead lets the package manager deal with it instead, which should work fine in all cases (either that or your package manager has a bug, but that's not esbuild's problem). There is one case where this new installation method doesn't work: if you pass the `--no-optional` flag to npm to disable the `optionalDependencies` feature. If you do this, you prevent esbuild from being installed. This is not a problem with esbuild because you are manually enabling a flag to change npm's behavior such that esbuild doesn't install correctly. However, people still want to do this. With this release, esbuild will now fall back to the old installation method if the new installation method fails. **THIS MAY NOT WORK.** The new `optionalDependencies` installation method is the only supported way to install esbuild with npm. The old downloading installation method was removed because it doesn't always work. The downloading method is only being provided to try to be helpful but it's not the supported installation method. If you pass `--no-optional` and the download fails due to some environment customization you did, the recommended fix is to just remove the `--no-optional` flag. * Support the new `.mts` and `.cts` TypeScript file extensions The upcoming version 4.5 of TypeScript has two new file extensions: `.mts` and `.cts`. Files with these extensions can be imported using the `.mjs` and `.cjs`, respectively. So the statement `import "./foo.mjs"` in TypeScript can actually succeed even if the file `./foo.mjs` doesn't exist on the file system as long as the file `./foo.mts` does exist. The import path with the `.mjs` extension is automatically re-routed to the corresponding file with the `.mts` extension at type-checking time by the TypeScript compiler. See [the TypeScript 4.5 beta announcement](https://devblogs.microsoft.com/typescript/announcing-typescript-4-5-beta/#new-file-extensions) for details. With this release, esbuild will also automatically rewrite `.mjs` to `.mts` and `.cjs` to `.cts` when resolving import paths to files on the file system. This should make it possible to bundle code written in this new style. In addition, the extensions `.mts` and `.cts` are now also considered valid TypeScript file extensions by default along with the `.ts` extension. * Fix invalid CSS minification of `margin` and `padding` ([#1657](https://github.com/evanw/esbuild/issues/1657)) CSS minification does collapsing of `margin` and `padding` related properties. For example: ```css /* Original CSS */ div { margin: auto; margin-top: 5px; margin-left: 5px; } /* Minified CSS */ div{margin:5px auto auto 5px} ``` However, while this works for the `auto` keyword, it doesn't work for other keywords. For example: ```css /* Original CSS */ div { margin: inherit; margin-top: 5px; margin-left: 5px; } /* Minified CSS */ div{margin:inherit;margin-top:5px;margin-left:5px} ``` Transforming this to `div{margin:5px inherit inherit 5px}`, as was done in previous releases of esbuild, is an invalid transformation and results in incorrect CSS. This release of esbuild fixes this CSS transformation bug. ## 0.13.3 * Support TypeScript type-only import/export specifiers ([#1637](https://github.com/evanw/esbuild/pull/1637)) This release adds support for a new TypeScript syntax feature in the upcoming version 4.5 of TypeScript. This feature lets you prefix individual imports and exports with the `type` keyword to indicate that they are types instead of values. This helps tools such as esbuild omit them from your source code, and is necessary because esbuild compiles files one-at-a-time and doesn't know at parse time which imports/exports are types and which are values. The new syntax looks like this: ```ts // Input TypeScript code import { type Foo } from 'foo' export { type Bar } // Output JavaScript code (requires "importsNotUsedAsValues": "preserve" in "tsconfig.json") import {} from "foo"; export {}; ``` See [microsoft/TypeScript#45998](https://github.com/microsoft/TypeScript/pull/45998) for full details. From what I understand this is a purely ergonomic improvement since this was already previously possible using a type-only import/export statements like this: ```ts // Input TypeScript code import type { Foo } from 'foo' export type { Bar } import 'foo' export {} // Output JavaScript code (requires "importsNotUsedAsValues": "preserve" in "tsconfig.json") import "foo"; export {}; ``` This feature was contributed by [@g-plane](https://github.com/g-plane). ## 0.13.2 * Fix `export {}` statements with `--tree-shaking=true` ([#1628](https://github.com/evanw/esbuild/issues/1628)) The new `--tree-shaking=true` option allows you to force-enable tree shaking in cases where it wasn't previously possible. One such case is when bundling is disabled and there is no output format configured, in which case esbuild just preserves the format of whatever format the input code is in. Enabling tree shaking in this context caused a bug where `export {}` statements were stripped. This release fixes the bug so `export {}` statements should now be preserved when you pass `--tree-shaking=true`. This bug only affected this new functionality and didn't affect existing scenarios. ## 0.13.1 * Fix the `esbuild` package in yarn 2+ The [yarn package manager](https://yarnpkg.com/) version 2 and above has a mode called [PnP](https://next.yarnpkg.com/features/pnp/) that installs packages inside zip files instead of using individual files on disk, and then hijacks node's `fs` module to pretend that paths to files inside the zip file are actually individual files on disk so that code that wasn't written specifically for yarn still works. Unfortunately that hijacking is incomplete and it still causes certain things to break such as using these zip file paths to create a JavaScript worker thread or to create a child process. This was an issue for the new `optionalDependencies` package installation strategy that was just released in version 0.13.0 since the binary executable is now inside of an installed package instead of being downloaded using an install script. When it's installed with yarn 2+ in PnP mode the binary executable is inside a zip file and can't be run. To work around this, esbuild detects yarn's PnP mode and copies the binary executable to a real file outside of the zip file. Unfortunately the code to do this didn't create the parent directory before writing to the file path. That caused esbuild's API to crash when it was run for the first time. This didn't come up during testing because the parent directory already existed when the tests were run. This release changes the location of the binary executable from a shared cache directory to inside the esbuild package itself, which should fix this crash. This problem only affected esbuild's JS API when it was run through yarn 2+ with PnP mode active. ## 0.13.0 **This release contains backwards-incompatible changes.** Since esbuild is before version 1.0.0, these changes have been released as a new minor version to reflect this (as [recommended by npm](https://docs.npmjs.com/cli/v6/using-npm/semver/)). You should either be pinning the exact version of `esbuild` in your `package.json` file or be using a version range syntax that only accepts patch upgrades such as `~0.12.0`. See the documentation about [semver](https://docs.npmjs.com/cli/v6/using-npm/semver/) for more information. * Allow tree shaking to be force-enabled and force-disabled ([#1518](https://github.com/evanw/esbuild/issues/1518), [#1610](https://github.com/evanw/esbuild/issues/1610), [#1611](https://github.com/evanw/esbuild/issues/1611), [#1617](https://github.com/evanw/esbuild/pull/1617)) This release introduces a breaking change that gives you more control over when tree shaking happens ("tree shaking" here refers to declaration-level dead code removal). Previously esbuild's tree shaking was automatically enabled or disabled for you depending on the situation and there was no manual override to change this. Specifically, tree shaking was only enabled either when bundling was enabled or when the output format was set to `iife` (i.e. wrapped in an immediately-invoked function expression). This was done to avoid issues with people appending code to output files in the `cjs` and `esm` formats and expecting that code to be able to reference code in the output file that isn't otherwise referenced. You now have the ability to explicitly force-enable or force-disable tree shaking to bypass this default behavior. This is a breaking change because there is already a setting for tree shaking that does something else, and it has been moved to a separate setting instead. The previous setting allowed you to control whether or not to ignore manual side-effect annotations, which is related to tree shaking since only side-effect free code can be removed as dead code. Specifically you can annotate function calls with `/* @__PURE__ */` to indicate that they can be removed if they are not used, and you can annotate packages with `"sideEffects": false` to indicate that imports of that package can be removed if they are not used. Being able to ignore these annotations is necessary because [they are sometimes incorrect](https://github.com/tensorflow/tfjs/issues/4248). This previous setting has been moved to a separate setting because it actually impacts dead-code removal within expressions, which also applies when minifying with tree-shaking disabled. ### Old behavior * CLI * Ignore side-effect annotations: `--tree-shaking=ignore-annotations` * JS * Ignore side-effect annotations: `treeShaking: 'ignore-annotations'` * Go * Ignore side-effect annotations: `TreeShaking: api.TreeShakingIgnoreAnnotations` ### New behavior * CLI * Ignore side-effect annotations: `--ignore-annotations` * Force-disable tree shaking: `--tree-shaking=false` * Force-enable tree shaking: `--tree-shaking=true` * JS * Ignore side-effect annotations: `ignoreAnnotations: true` * Force-disable tree shaking: `treeShaking: false` * Force-enable tree shaking: `treeShaking: true` * Go * Ignore side-effect annotations: `IgnoreAnnotations: true` * Force-disable tree shaking: `TreeShaking: api.TreeShakingFalse` * Force-enable tree shaking: `TreeShaking: api.TreeShakingTrue` * The npm package now uses `optionalDependencies` to install the platform-specific binary executable ([#286](https://github.com/evanw/esbuild/issues/286), [#291](https://github.com/evanw/esbuild/issues/291), [#319](https://github.com/evanw/esbuild/issues/319), [#347](https://github.com/evanw/esbuild/issues/347), [#369](https://github.com/evanw/esbuild/issues/369), [#547](https://github.com/evanw/esbuild/issues/547), [#565](https://github.com/evanw/esbuild/issues/565), [#789](https://github.com/evanw/esbuild/issues/789), [#921](https://github.com/evanw/esbuild/issues/921), [#1193](https://github.com/evanw/esbuild/issues/1193), [#1270](https://github.com/evanw/esbuild/issues/1270), [#1382](https://github.com/evanw/esbuild/issues/1382), [#1422](https://github.com/evanw/esbuild/issues/1422), [#1450](https://github.com/evanw/esbuild/issues/1450), [#1485](https://github.com/evanw/esbuild/issues/1485), [#1546](https://github.com/evanw/esbuild/issues/1546), [#1547](https://github.com/evanw/esbuild/pull/1547), [#1574](https://github.com/evanw/esbuild/issues/1574), [#1609](https://github.com/evanw/esbuild/issues/1609)) This release changes esbuild's installation strategy in an attempt to improve compatibility with edge cases such as custom registries, custom proxies, offline installations, read-only file systems, or when post-install scripts are disabled. It's being treated as a breaking change out of caution because it's a significant change to how esbuild works with JS package managers, and hasn't been widely tested yet. **The old installation strategy** manually downloaded the correct binary executable in a [post-install script](https://docs.npmjs.com/cli/v7/using-npm/scripts). The binary executable is hosted in a separate platform-specific npm package such as [`esbuild-darwin-64`](https://www.npmjs.com/package/esbuild-darwin-64). The install script first attempted to download the package via the `npm` command in case npm had custom network settings configured. If that didn't work, the install script attempted to download the package from https://registry.npmjs.org/ before giving up. This was problematic for many reasons including: * Not all of npm's settings can be forwarded due to npm bugs such as https://github.com/npm/cli/issues/2284, and npm has said these bugs will never be fixed. * Some people have configured their network environments such that downloading from https://registry.npmjs.org/ will hang instead of either succeeding or failing. * The installed package was broken if you used `npm --ignore-scripts` because then the post-install script wasn't run. Some people enable this option so that malicious packages must be run first before being able to do malicious stuff. **The new installation strategy** automatically downloads the correct binary executable using npm's `optionalDependencies` feature to depend on all esbuild packages for all platforms but only have the one for the current platform be installed. This is a built-in part of the package manager so my assumption is that it should work correctly in all of these edge cases that currently don't work. And if there's an issue with this, then the problem is with the package manager instead of with esbuild so this should hopefully reduce the maintenance burden on esbuild itself. Changing to this installation strategy has these drawbacks: * Old versions of certain package managers (specifically npm and yarn) print lots of useless log messages during the installation, at least one for each platform other than the current one. These messages are harmless and can be ignored. However, they are annoying. There is nothing I can do about this. If you have this problem, one solution is to upgrade your package manager to a newer version. * Installation will be significantly slower in old versions of npm, old versions of pnpm, and all versions of yarn. These package managers download all packages for all platforms even though they aren't needed and actually cannot be used. This problem has been fixed in npm and pnpm and the problem has been communicated to yarn: https://github.com/yarnpkg/berry/issues/3317. If you have this problem, one solution is to use a newer version of npm or pnpm as your package manager. * This installation strategy does not work if you use `npm --no-optional` since then the package with the binary executable is not installed. If you have this problem, the solution is to not pass the `--no-optional` flag when installing packages. * There is still a small post-install script but it's now optional in that the `esbuild` package should still function correctly if post-install scripts are disabled (such as with `npm --ignore-scripts`). This post-install script optimizes the installed package by replacing the `esbuild` JavaScript command shim with the actual binary executable at install time. This avoids the overhead of launching another `node` process when using the `esbuild` command. So keep in mind that installing with `--ignore-scripts` will result in a slower `esbuild` command. Despite the drawbacks of the new installation strategy, I believe this change is overall a good thing to move forward with. It should fix edge case scenarios where installing esbuild currently doesn't work at all, and this only comes at the expense of the install script working in a less-optimal way (but still working) if you are using an old version of npm. So I'm going to switch installation strategies and see how it goes. The platform-specific binary executables are still hosted on npm in the same way, so anyone who wrote code that downloads builds from npm using the instructions here should not have to change their code: https://esbuild.github.io/getting-started/#download-a-build. However, note that these platform-specific packages no longer specify the `bin` field in `package.json` so the `esbuild` command will no longer be automatically put on your path. The `bin` field had to be removed because of a collision with the `bin` field of the `esbuild` package (now that the `esbuild` package depends on all of these platform-specific packages as optional dependencies). In addition to the breaking changes above, the following features are also included in this release: * Treat `x` guarded by `typeof x !== 'undefined'` as side-effect free This is a small tree-shaking (i.e. dead code removal) improvement. Global identifier references are considered to potentially have side effects since they will throw a reference error if the global identifier isn't defined, and code with side effects cannot be removed as dead code. However, there's a somewhat-common case where the identifier reference is guarded by a `typeof` check to check that it's defined before accessing it. With this release, code that does this will now be considered to have no side effects which allows it to be tree-shaken: ```js // Original code var __foo = typeof foo !== 'undefined' && foo; var __bar = typeof bar !== 'undefined' && bar; console.log(__bar); // Old output (with --bundle, which enables tree-shaking) var __foo = typeof foo !== 'undefined' && foo; var __bar = typeof bar !== 'undefined' && bar; console.log(__bar); // New output (with --bundle, which enables tree-shaking) var __bar = typeof bar !== 'undefined' && bar; console.log(__bar); ``` ## 0.12.29 * Fix compilation of abstract class fields in TypeScript ([#1623](https://github.com/evanw/esbuild/issues/1623)) This release fixes a bug where esbuild could incorrectly include a TypeScript abstract class field in the compiled JavaScript output. This is incorrect because the official TypeScript compiler never does this. Note that this only happened in scenarios where TypeScript's `useDefineForClassFields` setting was set to `true` (or equivalently where TypeScript's `target` setting was set to `ESNext`). Here is the difference: ```js // Original code abstract class Foo { abstract foo: any; } // Old output class Foo { foo; } // New output class Foo { } ``` * Proxy from the `__require` shim to `require` ([#1614](https://github.com/evanw/esbuild/issues/1614)) Some background: esbuild's bundler emulates a CommonJS environment. The bundling process replaces the literal syntax `require()` with the referenced module at compile-time. However, other uses of `require` such as `require(someFunction())` are not bundled since the value of `someFunction()` depends on code evaluation, and esbuild does not evaluate code at compile-time. So it's possible for some references to `require` to remain after bundling. This was causing problems for some CommonJS code that was run in the browser and that expected `typeof require === 'function'` to be true (see [#1202](https://github.com/evanw/esbuild/issues/1202)), since the browser does not provide a global called `require`. Thus esbuild introduced a shim `require` function called `__require` (shown below) and replaced all references to `require` in the bundled code with `__require`: ```js var __require = x => { if (typeof require !== 'undefined') return require(x); throw new Error('Dynamic require of "' + x + '" is not supported'); }; ``` However, this broke code that referenced `require.resolve` inside the bundle, which could hypothetically actually work since you could assign your own implementation to `window.require.resolve` (see [#1579](https://github.com/evanw/esbuild/issues/1579)). So the implementation of `__require` was changed to this: ```js var __require = typeof require !== 'undefined' ? require : x => { throw new Error('Dynamic require of "' + x + '" is not supported'); }; ``` However, that broke code that assigned to `window.require` later on after the bundle was loaded ([#1614](https://github.com/evanw/esbuild/issues/1614)). So with this release, the code for `__require` now handles all of these edge cases: * `typeof require` is still `function` even if `window.require` is undefined * `window.require` can be assigned to either before or after the bundle is loaded * `require.resolve` and arbitrary other properties can still be accessed * `require` will now forward any number of arguments, not just the first one Handling all of these edge cases is only possible with the [Proxy API](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy). So the implementation of `__require` now looks like this: ```js var __require = (x => typeof require !== 'undefined' ? require : typeof Proxy !== 'undefined' ? new Proxy(x, { get: (a, b) => (typeof require !== 'undefined' ? require : a)[b] }) : x )(function(x) { if (typeof require !== 'undefined') return require.apply(this, arguments); throw new Error('Dynamic require of "' + x + '" is not supported'); }); ``` * Consider `typeof x` to have no side effects The `typeof` operator does not itself trigger any code evaluation so it can safely be removed if evaluating the operand does not cause any side effects. However, there is a special case of the `typeof` operator when the operand is an identifier expression. In that case no reference error is thrown if the referenced symbol does not exist (e.g. `typeof x` does not throw an error if there is no symbol named `x`). With this release, esbuild will now consider `typeof x` to have no side effects even if evaluating `x` would have side effects (i.e. would throw a reference error): ```js // Original code var unused = typeof React !== 'undefined'; // Old output var unused = typeof React !== 'undefined'; // New output ``` Note that there is actually an edge case where `typeof x` *can* throw an error: when `x` is being referenced inside of its TDZ, or temporal dead zone (i.e. before it's declared). This applies to `let`, `const`, and `class` symbols. However, esbuild doesn't currently handle TDZ rules so the possibility of errors thrown due to TDZ rules is not currently considered. This typically doesn't matter in real-world code so this hasn't been a priority to fix (and is actually tricky to fix with esbuild's current bundling approach). So esbuild may incorrectly remove a `typeof` expression that actually has side effects. However, esbuild already incorrectly did this in previous releases so its behavior regarding `typeof` and TDZ rules hasn't changed in this release. ## 0.12.28 * Fix U+30FB and U+FF65 in identifier names in ES5 vs. ES6+ ([#1599](https://github.com/evanw/esbuild/issues/1599)) The ES6 specification caused two code points that were previously valid in identifier names in ES5 to no longer be valid in identifier names in ES6+. The two code points are: * `U+30FB` i.e. `KATAKANA MIDDLE DOT` i.e. `・` * `U+FF65` i.e. `HALFWIDTH KATAKANA MIDDLE DOT` i.e. `･` This means that using ES6+ parsing rules will fail to parse some valid ES5 code, and generating valid ES5 code may fail to be parsed using ES6+ parsing rules. For example, esbuild would previously fail to parse `x.y･` even though it's valid ES5 code (since it's not valid ES6+ code) and esbuild could generate `{y･:x}` when minifying even though it's not valid ES6+ code (since it's valid ES5 code). This problem is the result of my incorrect assumption that ES6 is a superset of ES5. As of this release, esbuild will now parse a superset of ES5 and ES6+ and will now quote identifier names when possible if it's not considered to be a valid identifier name in either ES5 or ES6+. In other words, a union of ES5 and ES6 rules is used for parsing and the intersection of ES5 and ES6 rules is used for printing. * Fix `++` and `--` on class private fields when used with big integers ([#1600](https://github.com/evanw/esbuild/issues/1600)) Previously when esbuild lowered class private fields (e.g. `#foo`) to older JavaScript syntax, the transform of the `++` and `--` was not correct if the value is a big integer such as `123n`. The transform in esbuild is similar to Babel's transform which [has the same problem](https://github.com/babel/babel/issues/13756). Specifically, the code was transformed into code that either adds or subtracts the number `1` and `123n + 1` throws an exception in JavaScript. This problem has been fixed so this should now work fine starting with this release. ## 0.12.27 * Update JavaScript syntax feature compatibility tables ([#1594](https://github.com/evanw/esbuild/issues/1594)) Most JavaScript syntax feature compatibility data is able to be obtained automatically via https://kangax.github.io/compat-table/. However, they are missing data for quite a few new JavaScript features (see ([kangax/compat-table#1034](https://github.com/kangax/compat-table/issues/1034))) so data on these new features has to be added manually. This release manually adds a few new entries: * Top-level await This feature lets you use `await` at the top level of a module, outside of an `async` function. Doing this holds up the entire module instantiation operation until the awaited expression is resolved or rejected. This release marks this feature as supported in Edge 89, Firefox 89, and Safari 15 (it was already marked as supported in Chrome 89 and Node 14.8). The data source for this is https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/await. * Arbitrary module namespace identifier names This lets you use arbitrary strings as module namespace identifier names as long as they are valid UTF-16 strings. An example is `export { x as "🍕" }` which can then be imported as `import { "🍕" as y } from "./example.js"`. This release marks this feature as supported in Firefox 87 (it was already marked as supported in Chrome 90 and Node 16). The data source for this is https://bugzilla.mozilla.org/show_bug.cgi?id=1670044. I would also like to add data for Safari. They have recently added support for arbitrary module namespace identifier names (https://bugs.webkit.org/show_bug.cgi?id=217576) and `export * as` (https://bugs.webkit.org/show_bug.cgi?id=214379). However, I have no idea how to determine which Safari release these bugs correspond to so this compatibility data for Safari has been omitted. * Avoid unnecessary additional log messages after the server is stopped ([#1589](https://github.com/evanw/esbuild/issues/1589)) There is a development server built in to esbuild which is accessible via the `serve()` API call. This returns a promise that resolves to an object with a `stop()` method that immediately terminates the development server. Previously calling this could cause esbuild to print stray log messages since `stop()` could cause plugins to be unregistered while a build is still in progress. With this release, calling `stop()` no longer terminates the development server immediately. It now waits for any active builds to finish first so the builds are not interrupted and left in a confusing state. * Fix an accidental dependency on Go ≥1.17.0 ([#1585](https://github.com/evanw/esbuild/pull/1585)) The source code of this release no longer uses the `math.MaxInt` constant that was introduced in Go version 1.17.0. This constant was preventing esbuild from being compiled on Go version <1.17.0. This fix was contributed by [@davezuko](https://github.com/davezuko). ## 0.12.26 * Add `--analyze` to print information about the bundle ([#1568](https://github.com/evanw/esbuild/issues/1568)) The `--metafile=` flag tells esbuild to write information about the bundle into the provided metadata file in JSON format. It contains information about the input files and which other files each one imports, as well as the output files and which input files they include. This information is sufficient to answer many questions such as: * Which files are in my bundle? * What's are the biggest files in my bundle? * Why is this file included in my bundle? Previously you had to either write your own code to answer these questions, or use another tool such as https://bundle-buddy.com/esbuild to visualize the data. Starting with this release you can now also use `--analyze` to enable esbuild's built-in visualizer. It looks like this: ``` $ esbuild --bundle example.jsx --outfile=out.js --minify --analyze out.js 27.6kb ⚡ Done in 6ms out.js 27.6kb 100.0% ├ node_modules/react-dom/cjs/react-dom-server.browser.production.min.js 19.2kb 69.8% ├ node_modules/react/cjs/react.production.min.js 5.9kb 21.4% ├ node_modules/object-assign/index.js 965b 3.4% ├ example.jsx 137b 0.5% ├ node_modules/react-dom/server.browser.js 50b 0.2% └ node_modules/react/index.js 50b 0.2% ``` This tells you what input files were bundled into each output file as well as the final minified size contribution of each input file as well as the percentage of the output file it takes up. You can also enable verbose analysis with `--analyze=verbose` to see why each input file was included (i.e. which files imported it from the entry point file): ``` $ esbuild --bundle example.jsx --outfile=out.js --minify --analyze=verbose out.js 27.6kb ⚡ Done in 6ms out.js ─────────────────────────────────────────────────────────────────── 27.6kb ─ 100.0% ├ node_modules/react-dom/cjs/react-dom-server.browser.production.min.js ─ 19.2kb ── 69.8% │ └ node_modules/react-dom/server.browser.js │ └ example.jsx ├ node_modules/react/cjs/react.production.min.js ───────────────────────── 5.9kb ── 21.4% │ └ node_modules/react/index.js │ └ example.jsx ├ node_modules/object-assign/index.js ──────────────────────────────────── 965b ──── 3.4% │ └ node_modules/react-dom/cjs/react-dom-server.browser.production.min.js │ └ node_modules/react-dom/server.browser.js │ └ example.jsx ├ example.jsx ──────────────────────────────────────────────────────────── 137b ──── 0.5% ├ node_modules/react-dom/server.browser.js ──────────────────────────────── 50b ──── 0.2% │ └ example.jsx └ node_modules/react/index.js ───────────────────────────────────────────── 50b ──── 0.2% └ example.jsx ``` There is also a JS API for this: ```js const result = await esbuild.build({ metafile: true, ... }) console.log(await esbuild.analyzeMetafile(result.metafile, { verbose: true, })) ``` and a Go API: ```js result := api.Build(api.BuildOptions{ Metafile: true, ... }) fmt.Println(api.AnalyzeMetafile(result.Metafile, api.AnalyzeMetafileOptions{ Verbose: true, })) ``` Note that this is not the only way to visualize this data. If you want a visualization that's different than the information displayed here, you can easily build it yourself using the information in the metafile that is generated with the `--metafile=` flag. Also note that this data is intended for humans, not machines. The specific format of this data may change over time which will likely break any tools that try to parse it. You should not write a tool to parse this data. You should be using the information in the JSON metadata file instead. Everything in this visualization is derived from the JSON metadata so you are not losing out on any information by not using esbuild's output. * Allow `require.resolve` in non-node builds ([#1579](https://github.com/evanw/esbuild/issues/1579)) With this release, you can now use `require.resolve` in builds when the target platform is set to `browser` instead of `node` as long as the function `window.require.resolve` exists somehow. This was already possible when the platform is `node` but when the platform is `browser`, esbuild generates a no-op shim `require` function for compatibility reasons (e.g. because some code expects `typeof require` must be `"function"` even in the browser). The shim previously had a fallback to `window.require` if it exists, but additional properties of the `require` function such as `require.resolve` were not copied over to the shim. Now the shim function is only used if `window.require` is undefined so additional properties such as `require.resolve` should now work. This change was contributed by [@screetBloom](https://github.com/screetBloom). ## 0.12.25 * Fix a TypeScript parsing edge case with the postfix `!` operator ([#1560](https://github.com/evanw/esbuild/issues/1560)) This release fixes a bug with esbuild's TypeScript parser where the postfix `!` operator incorrectly terminated a member expression after the `new` operator: ```js // Original input new Foo!.Bar(); // Old output new Foo().Bar(); // New output new Foo.Bar(); ``` The problem was that `!` was considered a postfix operator instead of part of a member expression. It is now considered to be part of a member expression instead, which fixes this edge case. * Fix a parsing crash with nested private brand checks This release fixes a bug in the parser where code of the form `#a in #b in c` caused a crash. This code now causes a syntax error instead. Private identifiers are allowed when followed by `in`, but only if the operator precedence level is such that the `in` operator is allowed. The parser was missing the operator precedence check. * Publish x86-64 binary executables for illumos ([#1562](https://github.com/evanw/esbuild/pull/1562)) This release adds support for the [illumos](https://www.illumos.org/) operating system, which is related to Solaris and SunOS. Support for this platform was contributed by [@hadfl](https://github.com/hadfl). ## 0.12.24 * Fix an edge case with direct `eval` and variable renaming Use of the direct `eval` construct causes all variable names in the scope containing the direct `eval` and all of its parent scopes to become "pinned" and unable to be renamed. This is because the dynamically-evaluated code is allowed to reference any of those variables by name. When this happens esbuild avoids renaming any of these variables, which effectively disables minification for most of the file, and avoids renaming any non-pinned variables to the name of a pinned variable. However, there was previously a bug where the pinned variable name avoidance only worked for pinned variables in the top-level scope but not in nested scopes. This could result in a non-pinned variable being incorrectly renamed to the name of a pinned variable in certain cases. For example: ```js // Input to esbuild return function($) { function foo(arg) { return arg + $; } // Direct "eval" here prevents "$" from being renamed // Repeated "$" puts "$" at the top of the character frequency histogram return eval(foo($$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$)) }(2); ``` When this code is minified with `--minify-identifiers`, the non-pinned variable `arg` is incorrectly transformed into `$` resulting in a name collision with the nested pinned variable `$`: ```js // Old output from esbuild (incorrect) return function($) { function foo($) { return $ + $; } return eval(foo($$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$)); }(2); ``` This is because the non-pinned variable `arg` is renamed to the top character in the character frequency histogram `$` (esbuild uses a character frequency histogram for smaller gzipped output sizes) and the pinned variable `$` was incorrectly not present in the list of variable names to avoid. With this release, the output is now correct: ```js // New output from esbuild (correct) return function($) { function foo(n) { return n + $; } return eval(foo($$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$)); }(2); ``` Note that even when esbuild handles direct `eval` correctly, using direct `eval` is not recommended because it disables minification for the file and likely won't work correctly in the presence of scope hoisting optimizations. See https://esbuild.github.io/link/direct-eval for more details. ## 0.12.23 * Parsing of rest arguments in certain TypeScript types ([#1553](https://github.com/evanw/esbuild/issues/1553)) This release implements parsing of rest arguments inside object destructuring inside arrow functions inside TypeScript type declarations. Support for rest arguments in this specific syntax was not previously implemented. The following code was incorrectly considered a syntax error before this release, but is no longer considered a syntax error: ```ts type F = ({ ...rest }) => void; ``` * Fix error message for `watch: true` and `buildSync` ([#1552](https://github.com/evanw/esbuild/issues/1552)) Watch mode currently only works with the `build` API. Previously using watch mode with the `buildSync` API caused a confusing error message. This release explicitly disallows doing this, so the error message is now more clear. * Fix an minification bug with the `--keep-names` option ([#1552](https://github.com/evanw/esbuild/issues/1552)) This release fixes a subtle bug that happens with `--keep-names --minify` and nested function declarations in strict mode code. It can be triggered by the following code, which was being compiled incorrectly under those flags: ```js export function outer() { { function inner() { return Math.random(); } const x = inner(); console.log(x); } } outer(); ``` The bug was caused by an unfortunate interaction between a few of esbuild's behaviors: 1. Function declarations inside of nested scopes behave differently in different situations, so esbuild rewrites this function declaration to a local variable initialized to a function expression instead so that it behaves the same in all situations. More specifically, the interpretation of such function declarations depends on whether or not it currently exists in a strict mode context: ``` > (function(){ { function x(){} } return x })() function x() {} > (function(){ 'use strict'; { function x(){} } return x })() ❌ Uncaught ReferenceError: x is not defined ``` The bundling process sometimes erases strict mode context. For example, different files may have different strict mode status but may be merged into a single file which all shares the same strict mode status. Also, files in ESM format are automatically in strict mode but a bundle output file in IIFE format may not be executed in strict mode. Transforming the nested `function` to a `let` in strict mode and a `var` in non-strict mode means esbuild's output will behave reliably in different environments. 2. The "keep names" feature adds automatic calls to the built-in `__name` helper function to assign the original name to the `.name` property of the minified function object at run-time. That transforms the code into this: ```js let inner = function() { return Math.random(); }; __name(inner, "inner"); const x = inner(); console.log(x); ``` This injected helper call does not count as a use of the associated function object so that dead-code elimination will still remove the function object as dead code if nothing else uses it. Otherwise dead-code elimination would stop working when the "keep names" feature is enabled. 3. Minification enables an optimization where an initialized variable with a single use immediately following that variable is transformed by inlining the initializer into the use. So for example `var a = 1; return a` is transformed into `return 1`. This code matches this pattern (initialized single-use variable + use immediately following that variable) so the optimization does the inlining, which transforms the code into this: ```js __name(function() { return Math.random(); }, "inner"); const x = inner(); console.log(x); ``` The code is now incorrect because `inner` actually has two uses, although only one was actually counted. This inlining optimization will now be avoided in this specific case, which fixes the bug without regressing dead-code elimination or initialized variable inlining in any other cases. ## 0.12.22 * Make HTTP range requests more efficient ([#1536](https://github.com/evanw/esbuild/issues/1536)) The local HTTP server built in to esbuild supports [range requests](https://developer.mozilla.org/en-US/docs/Web/HTTP/Range_requests), which are necessary for video playback in Safari. This means you can now use `