package/LICENSE000644 0000002061 3560116604 010264 0ustar00000000 000000 MIT License Copyright (c) 2019 Alexander Reardon Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.package/dist/memoize-one.cjs.js.flow000644 0000000527 3560116604 014535 0ustar00000000 000000 // @flow // These types are not as powerful as the TypeScript types, but they get the job done export type EqualityFn = (newArgs: mixed[], lastArgs: mixed[]) => boolean; // default export declare export default function memoizeOne mixed>( fn: ResultFn, isEqual?: EqualityFn, ): ResultFn & { clear: () => void }; package/src/memoize-one.js.flow000644 0000000527 3560116604 013603 0ustar00000000 000000 // @flow // These types are not as powerful as the TypeScript types, but they get the job done export type EqualityFn = (newArgs: mixed[], lastArgs: mixed[]) => boolean; // default export declare export default function memoizeOne mixed>( fn: ResultFn, isEqual?: EqualityFn, ): ResultFn & { clear: () => void }; package/dist/memoize-one.cjs.js000644 0000002530 3560116604 013563 0ustar00000000 000000 'use strict'; var safeIsNaN = Number.isNaN || function ponyfill(value) { return typeof value === 'number' && value !== value; }; function isEqual(first, second) { if (first === second) { return true; } if (safeIsNaN(first) && safeIsNaN(second)) { return true; } return false; } function areInputsEqual(newInputs, lastInputs) { if (newInputs.length !== lastInputs.length) { return false; } for (var i = 0; i < newInputs.length; i++) { if (!isEqual(newInputs[i], lastInputs[i])) { return false; } } return true; } function memoizeOne(resultFn, isEqual) { if (isEqual === void 0) { isEqual = areInputsEqual; } var cache = null; function memoized() { var newArgs = []; for (var _i = 0; _i < arguments.length; _i++) { newArgs[_i] = arguments[_i]; } if (cache && cache.lastThis === this && isEqual(newArgs, cache.lastArgs)) { return cache.lastResult; } var lastResult = resultFn.apply(this, newArgs); cache = { lastResult: lastResult, lastArgs: newArgs, lastThis: this, }; return lastResult; } memoized.clear = function clear() { cache = null; }; return memoized; } module.exports = memoizeOne; package/dist/memoize-one.esm.js000644 0000002516 3560116604 013574 0ustar00000000 000000 var safeIsNaN = Number.isNaN || function ponyfill(value) { return typeof value === 'number' && value !== value; }; function isEqual(first, second) { if (first === second) { return true; } if (safeIsNaN(first) && safeIsNaN(second)) { return true; } return false; } function areInputsEqual(newInputs, lastInputs) { if (newInputs.length !== lastInputs.length) { return false; } for (var i = 0; i < newInputs.length; i++) { if (!isEqual(newInputs[i], lastInputs[i])) { return false; } } return true; } function memoizeOne(resultFn, isEqual) { if (isEqual === void 0) { isEqual = areInputsEqual; } var cache = null; function memoized() { var newArgs = []; for (var _i = 0; _i < arguments.length; _i++) { newArgs[_i] = arguments[_i]; } if (cache && cache.lastThis === this && isEqual(newArgs, cache.lastArgs)) { return cache.lastResult; } var lastResult = resultFn.apply(this, newArgs); cache = { lastResult: lastResult, lastArgs: newArgs, lastThis: this, }; return lastResult; } memoized.clear = function clear() { cache = null; }; return memoized; } export { memoizeOne as default }; package/dist/memoize-one.js000644 0000003370 3560116604 013010 0ustar00000000 000000 (function (global, factory) { typeof exports === 'object' && typeof module !== 'undefined' ? module.exports = factory() : typeof define === 'function' && define.amd ? define(factory) : (global = typeof globalThis !== 'undefined' ? globalThis : global || self, global.memoizeOne = factory()); })(this, (function () { 'use strict'; var safeIsNaN = Number.isNaN || function ponyfill(value) { return typeof value === 'number' && value !== value; }; function isEqual(first, second) { if (first === second) { return true; } if (safeIsNaN(first) && safeIsNaN(second)) { return true; } return false; } function areInputsEqual(newInputs, lastInputs) { if (newInputs.length !== lastInputs.length) { return false; } for (var i = 0; i < newInputs.length; i++) { if (!isEqual(newInputs[i], lastInputs[i])) { return false; } } return true; } function memoizeOne(resultFn, isEqual) { if (isEqual === void 0) { isEqual = areInputsEqual; } var cache = null; function memoized() { var newArgs = []; for (var _i = 0; _i < arguments.length; _i++) { newArgs[_i] = arguments[_i]; } if (cache && cache.lastThis === this && isEqual(newArgs, cache.lastArgs)) { return cache.lastResult; } var lastResult = resultFn.apply(this, newArgs); cache = { lastResult: lastResult, lastArgs: newArgs, lastThis: this, }; return lastResult; } memoized.clear = function clear() { cache = null; }; return memoized; } return memoizeOne; })); package/package.json000644 0000006153 3560116604 011553 0ustar00000000 000000 { "name": "memoize-one", "version": "6.0.0", "description": "A memoization library which only remembers the latest invocation", "main": "dist/memoize-one.cjs.js", "types": "dist/memoize-one.d.ts", "module": "dist/memoize-one.esm.js", "sideEffects": false, "author": "Alex Reardon ", "license": "MIT", "repository": { "type": "git", "url": "https://github.com/alexreardon/memoize-one.git" }, "files": [ "/dist", "/src" ], "size-limit": [ { "path": "dist/memoize-one.min.js", "limit": "234B" }, { "path": "dist/memoize-one.js", "limit": "234B" }, { "path": "dist/memoize-one.cjs.js", "limit": "230B" }, { "path": "dist/memoize-one.esm.js", "limit": "246B" } ], "keywords": [ "memoize", "memoization", "cache", "performance" ], "dependencies": {}, "devDependencies": { "@size-limit/preset-small-lib": "^5.0.4", "@types/benchmark": "^2.1.1", "@types/jest": "^27.0.2", "@types/lodash.isequal": "^4.5.5", "@types/lodash.memoize": "^4.1.6", "@types/node": "^16.10.1", "@typescript-eslint/eslint-plugin": "^4.31.2", "@typescript-eslint/parser": "^4.31.2", "benchmark": "^2.1.4", "cross-env": "^7.0.3", "eslint": "7.32.0", "eslint-config-prettier": "^8.3.0", "eslint-plugin-jest": "^24.4.2", "eslint-plugin-prettier": "^4.0.0", "expect-type": "^0.12.0", "fast-memoize": "^2.5.2", "jest": "^27.2.2", "lodash.isequal": "^4.5.0", "lodash.memoize": "^4.1.2", "markdown-table": "^3.0.1", "mem": "^9.0.1", "memoizee": "^0.4.15", "moize": "^6.1.0", "nanocolors": "^0.2.9", "ora": "^6.0.1", "prettier": "2.4.1", "rimraf": "3.0.2", "rollup": "^2.57.0", "rollup-plugin-replace": "^2.2.0", "rollup-plugin-terser": "^7.0.2", "rollup-plugin-typescript": "^1.0.1", "size-limit": "^5.0.4", "ts-jest": "^27.0.5", "ts-node": "^10.2.1", "tslib": "^2.3.1", "typescript": "^4.4.3" }, "config": { "prettier_target": "src/**/*.{ts,js,jsx,md,json} test/**/*.{ts,js,jsx,md,json}" }, "scripts": { "validate": "yarn prettier:check && yarn eslint:check && yarn typescript:check", "test": "yarn jest", "test:size": "yarn build && yarn size-limit", "typescript:check": "yarn tsc --noEmit", "prettier:check": "yarn prettier --debug-check $npm_package_config_prettier_target", "prettier:write": "yarn prettier --write $npm_package_config_prettier_target", "eslint:check": "eslint $npm_package_config_prettier_target", "build": "yarn build:clean && yarn build:dist && yarn build:typescript && yarn build:flow", "build:clean": "yarn rimraf dist", "build:dist": "yarn rollup -c", "build:typescript": "yarn tsc ./src/memoize-one.ts --emitDeclarationOnly --declaration --outDir ./dist", "build:flow": "cp src/memoize-one.js.flow dist/memoize-one.cjs.js.flow", "perf": "yarn ts-node ./benchmarks/shallow-equal.ts", "perf:library-comparison": "yarn build && node ./benchmarks/library-comparison.js", "prepublishOnly": "yarn build" } } package/README.md000644 0000052710 3560116604 010544 0ustar00000000 000000 # memoize-one A memoization library that only caches the result of the most recent arguments. [![npm](https://img.shields.io/npm/v/memoize-one.svg)](https://www.npmjs.com/package/memoize-one) ![types](https://img.shields.io/badge/types-typescript%20%7C%20flow-blueviolet) [![minzip](https://img.shields.io/bundlephobia/minzip/memoize-one.svg)](https://www.npmjs.com/package/memoize-one) [![Downloads per month](https://img.shields.io/npm/dm/memoize-one.svg)](https://www.npmjs.com/package/memoize-one) ## Rationale Unlike other memoization libraries, `memoize-one` only remembers the latest arguments and result. No need to worry about cache busting mechanisms such as `maxAge`, `maxSize`, `exclusions` and so on, which can be prone to memory leaks. A function memoized with `memoize-one` simply remembers the last arguments, and if the memoized function is next called with the same arguments then it returns the previous result. > For working with promises, [@Kikobeats](https://github.com/Kikobeats) has built [async-memoize-one](https://github.com/microlinkhq/async-memoize-one). ## Usage ```js // memoize-one uses the default import import memoizeOne from 'memoize-one'; function add(a, b) { return a + b; } const memoizedAdd = memoizeOne(add); memoizedAdd(1, 2); // add function: is called // [new value returned: 3] memoizedAdd(1, 2); // add function: not called // [cached result is returned: 3] memoizedAdd(2, 3); // add function: is called // [new value returned: 5] memoizedAdd(2, 3); // add function: not called // [cached result is returned: 5] memoizedAdd(1, 2); // add function: is called // [new value returned: 3] // 👇 // While the result of `add(1, 2)` was previously cached // `(1, 2)` was not the *latest* arguments (the last call was `(2, 3)`) // so the previous cached result of `(1, 3)` was lost ``` ## Installation ```bash # yarn yarn add memoize-one # npm npm install memoize-one --save ``` ## Function argument equality By default, we apply our own _fast_ and _relatively naive_ equality function to determine whether the arguments provided to your function are equal. You can see the full code here: [are-inputs-equal.ts](https://github.com/alexreardon/memoize-one/blob/master/src/are-inputs-equal.ts). (By default) function arguments are considered equal if: 1. there is same amount of arguments 2. each new argument has strict equality (`===`) with the previous argument 3. **[special case]** if two arguments are not `===` and they are both `NaN` then the two arguments are treated as equal What this looks like in practice: ```js import memoizeOne from 'memoize-one'; // add all numbers provided to the function const add = (...args = []) => args.reduce((current, value) => { return current + value; }, 0); const memoizedAdd = memoizeOne(add); ``` > 1. there is same amount of arguments ```js memoizedAdd(1, 2); // the amount of arguments has changed, so underlying add function is called memoizedAdd(1, 2, 3); ``` > 2. new arguments have strict equality (`===`) with the previous argument ```js memoizedAdd(1, 2); // each argument is `===` to the last argument, so cache is used memoizedAdd(1, 2); // second argument has changed, so add function is called again memoizedAdd(1, 3); // the first value is not `===` to the previous first value (1 !== 3) // so add function is called again memoizedAdd(3, 1); ``` > 3. **[special case]** if the arguments are not `===` and they are both `NaN` then the argument is treated as equal ```js memoizedAdd(NaN); // Even though NaN !== NaN these arguments are // treated as equal as they are both `NaN` memoizedAdd(NaN); ``` ## Custom equality function You can also pass in a custom function for checking the equality of two sets of arguments ```js const memoized = memoizeOne(fn, isEqual); ``` An equality function should return `true` if the arguments are equal. If `true` is returned then the wrapped function will not be called. **Tip**: A custom equality function needs to compare `Arrays`. The `newArgs` array will be a new reference every time so a simple `newArgs === lastArgs` will always return `false`. Equality functions are not called if the `this` context of the function has changed (see below). Here is an example that uses a [lodash.isEqual](https://lodash.com/docs/4.17.15#isEqual) deep equal equality check > `lodash.isequal` correctly handles deep comparing two arrays ```js import memoizeOne from 'memoize-one'; import isDeepEqual from 'lodash.isequal'; const identity = (x) => x; const shallowMemoized = memoizeOne(identity); const deepMemoized = memoizeOne(identity, isDeepEqual); const result1 = shallowMemoized({ foo: 'bar' }); const result2 = shallowMemoized({ foo: 'bar' }); result1 === result2; // false - different object reference const result3 = deepMemoized({ foo: 'bar' }); const result4 = deepMemoized({ foo: 'bar' }); result3 === result4; // true - arguments are deep equal ``` The equality function needs to conform to the `EqualityFn` `type`: ```ts // TFunc is the function being memoized type EqualityFn any> = ( newArgs: Parameters, lastArgs: Parameters, ) => boolean; // You can import this type import type { EqualityFn } from 'memoize-one'; ``` The `EqualityFn` type allows you to create equality functions that are extremely typesafe. You are welcome to provide your own less type safe equality functions. Here are some examples of equality functions which are ordered by most type safe, to least type safe:
Example equality function types

```ts // the function we are going to memoize function add(first: number, second: number): number { return first + second; } // Some options for our equality function // ↑ stronger types // ↓ weaker types // ✅ exact parameters of `add` { const isEqual = function (first: Parameters, second: Parameters) { return true; }; expectTypeOf().toMatchTypeOf>(); } // ✅ tuple of the correct types { const isEqual = function (first: [number, number], second: [number, number]) { return true; }; expectTypeOf().toMatchTypeOf>(); } // ❌ tuple of incorrect types { const isEqual = function (first: [number, string], second: [number, number]) { return true; }; expectTypeOf().not.toMatchTypeOf>(); } // ✅ array of the correct types { const isEqual = function (first: number[], second: number[]) { return true; }; expectTypeOf().toMatchTypeOf>(); } // ❌ array of incorrect types { const isEqual = function (first: string[], second: number[]) { return true; }; expectTypeOf().not.toMatchTypeOf>(); } // ✅ tuple of 'unknown' { const isEqual = function (first: [unknown, unknown], second: [unknown, unknown]) { return true; }; expectTypeOf().toMatchTypeOf>(); } // ❌ tuple of 'unknown' of incorrect length { const isEqual = function (first: [unknown, unknown, unknown], second: [unknown, unknown]) { return true; }; expectTypeOf().not.toMatchTypeOf>(); } // ✅ array of 'unknown' { const isEqual = function (first: unknown[], second: unknown[]) { return true; }; expectTypeOf().toMatchTypeOf>(); } // ✅ spread of 'unknown' { const isEqual = function (...first: unknown[]) { return !!first; }; expectTypeOf().toMatchTypeOf>(); } // ✅ tuple of 'any' { const isEqual = function (first: [any, any], second: [any, any]) { return true; }; expectTypeOf().toMatchTypeOf>(); } // ❌ tuple of 'any' or incorrect size { const isEqual = function (first: [any, any, any], second: [any, any]) { return true; }; expectTypeOf().not.toMatchTypeOf>(); } // ✅ array of 'any' { const isEqual = function (first: any[], second: any[]) { return true; }; expectTypeOf().toMatchTypeOf>(); } // ✅ two arguments of type any { const isEqual = function (first: any, second: any) { return true; }; expectTypeOf().toMatchTypeOf>(); } // ✅ a single argument of type any { const isEqual = function (first: any) { return true; }; expectTypeOf().toMatchTypeOf>(); } // ✅ spread of any type { const isEqual = function (...first: any[]) { return true; }; expectTypeOf().toMatchTypeOf>(); } ```

## `this` ### `memoize-one` correctly respects `this` control This library takes special care to maintain, and allow control over the the `this` context for **both** the original function being memoized as well as the returned memoized function. Both the original function and the memoized function's `this` context respect [all the `this` controlling techniques](https://github.com/getify/You-Dont-Know-JS/blob/master/this%20%26%20object%20prototypes/ch2.md): - new bindings (`new`) - explicit binding (`call`, `apply`, `bind`); - implicit binding (call site: `obj.foo()`); - default binding (`window` or `undefined` in `strict mode`); - fat arrow binding (binding to lexical `this`) - ignored this (pass `null` as `this` to explicit binding) ### Changes to `this` is considered an argument change Changes to the running context (`this`) of a function can result in the function returning a different value even though its arguments have stayed the same: ```js function getA() { return this.a; } const temp1 = { a: 20, }; const temp2 = { a: 30, }; getA.call(temp1); // 20 getA.call(temp2); // 30 ``` Therefore, in order to prevent against unexpected results, `memoize-one` takes into account the current execution context (`this`) of the memoized function. If `this` is different to the previous invocation then it is considered a change in argument. [further discussion](https://github.com/alexreardon/memoize-one/issues/3). Generally this will be of no impact if you are not explicity controlling the `this` context of functions you want to memoize with [explicit binding](https://github.com/getify/You-Dont-Know-JS/blob/master/this%20%26%20object%20prototypes/ch2.md#explicit-binding) or [implicit binding](https://github.com/getify/You-Dont-Know-JS/blob/master/this%20%26%20object%20prototypes/ch2.md#implicit-binding). `memoize-One` will detect when you are manipulating `this` and will then consider the `this` context as an argument. If `this` changes, it will re-execute the original function even if the arguments have not changed. ## Clearing the memoization cache A `.clear()` property is added to memoized functions to allow you to clear it's memoization cache. This is helpful if you want to: - Release memory - Allow the underlying function to be called again without having to change arguments ```ts import memoizeOne from 'memoize-one'; function add(a: number, b: number): number { return a + b; } const memoizedAdd = memoizeOne(add); // first call - not memoized const first = memoizedAdd(1, 2); // second call - cache hit (underlying function not called) const second = memoizedAdd(1, 2); // 👋 clearing memoization cache memoizedAdd.clear(); // third call - not memoized (cache was cleared) const third = memoizedAdd(1, 2); ``` ## When your result function `throw`s > There is no caching when your result function throws If your result function `throw`s then the memoized function will also throw. The throw will not break the memoized functions existing argument cache. It means the memoized function will pretend like it was never called with arguments that made it `throw`. ```js const canThrow = (name: string) => { console.log('called'); if (name === 'throw') { throw new Error(name); } return { name }; }; const memoized = memoizeOne(canThrow); const value1 = memoized('Alex'); // console.log => 'called' const value2 = memoized('Alex'); // result function not called console.log(value1 === value2); // console.log => true try { memoized('throw'); // console.log => 'called' } catch (e) { firstError = e; } try { memoized('throw'); // console.log => 'called' // the result function was called again even though it was called twice // with the 'throw' string } catch (e) { secondError = e; } console.log(firstError !== secondError); const value3 = memoized('Alex'); // result function not called as the original memoization cache has not been busted console.log(value1 === value3); // console.log => true ``` ## Function properties Functions memoized with `memoize-one` do not preserve any properties on the function object. > This behaviour correctly reflected in the TypeScript types ```ts import memoizeOne from 'memoize-one'; function add(a, b) { return a + b; } add.hello = 'hi'; console.log(typeof add.hello); // string const memoized = memoizeOne(add); // hello property on the `add` was not preserved console.log(typeof memoized.hello); // undefined ``` If you feel strongly that `memoize-one` _should_ preserve function properties, please raise an issue. This decision was made in order to keep `memoize-one` as light as possible. For _now_, the `.length` property of a function is not preserved on the memoized function ```ts import memoizeOne from 'memoize-one'; function add(a, b) { return a + b; } console.log(add.length); // 2 const memoized = memoizeOne(add); console.log(memoized.length); // 0 ``` There is no (great) way to correctly set the `.length` property of the memoized function while also supporting ie11. Once we [remove ie11 support](https://github.com/alexreardon/memoize-one/issues/125) then we will set the `.length` property of the memoized function to match the original function [→ discussion](https://github.com/alexreardon/memoize-one/pull/124). ## Memoized function `type` The resulting function you get back from `memoize-one` has *almost* the same `type` as the function that you are memoizing ```ts declare type MemoizedFn any> = { clear: () => void; (this: ThisParameterType, ...args: Parameters): ReturnType; }; ``` - the same call signature as the function being memoized - a `.clear()` function property added - other function object properties on `TFunc` as not carried over You are welcome to use the `MemoizedFn` generic directly from `memoize-one` if you like: ```ts import memoize, { MemoizedFn } from 'memoize-one'; import isDeepEqual from 'lodash.isequal'; import { expectTypeOf } from 'expect-type'; // Takes any function: TFunc, and returns a Memoized function withDeepEqual any>(fn: TFunc): MemoizedFn { return memoize(fn, isDeepEqual); } function add(first: number, second: number): number { return first + second; } const memoized = withDeepEqual(add); expectTypeOf().toEqualTypeOf>(); ``` In this specific example, this type would have been correctly inferred too ```ts import memoize, { MemoizedFn } from 'memoize-one'; import isDeepEqual from 'lodash.isequal'; import { expectTypeOf } from 'expect-type'; // return type of MemoizedFn is inferred function withDeepEqual any>(fn: TFunc) { return memoize(fn, isDeepEqual); } function add(first: number, second: number): number { return first + second; } const memoized = withDeepEqual(add); // type test still passes expectTypeOf().toEqualTypeOf>(); ``` ## Performance 🚀 ### Tiny `memoize-one` is super lightweight at [![min](https://img.shields.io/bundlephobia/min/memoize-one.svg?label=)](https://www.npmjs.com/package/memoize-one) minified and [![minzip](https://img.shields.io/bundlephobia/minzip/memoize-one.svg?label=)](https://www.npmjs.com/package/memoize-one) gzipped. (`1KB` = `1,024 Bytes`) ### Extremely fast `memoize-one` performs better or on par with than other popular memoization libraries for the purpose of remembering the latest invocation. The comparisons are not exhaustive and are primarily to show that `memoize-one` accomplishes remembering the latest invocation really fast. There is variability between runs. The benchmarks do not take into account the differences in feature sets, library sizes, parse time, and so on.
Expand for results

node version `16.11.1` You can run this test in the repo by: 1. Add `"type": "module"` to the `package.json` (why is things so hard) 2. Run `yarn perf:library-comparison` **no arguments** | Position | Library | Operations per second | | -------- | -------------------------------------------- | --------------------- | | 1 | memoize-one | 80,112,981 | | 2 | moize | 72,885,631 | | 3 | memoizee | 35,550,009 | | 4 | mem (JSON.stringify strategy) | 4,610,532 | | 5 | lodash.memoize (JSON.stringify key resolver) | 3,708,945 | | 6 | no memoization | 505 | | 7 | fast-memoize | 504 | **single primitive argument** | Position | Library | Operations per second | | -------- | -------------------------------------------- | --------------------- | | 1 | fast-memoize | 45,482,711 | | 2 | moize | 34,810,659 | | 3 | memoize-one | 29,030,828 | | 4 | memoizee | 23,467,065 | | 5 | mem (JSON.stringify strategy) | 3,985,223 | | 6 | lodash.memoize (JSON.stringify key resolver) | 3,369,297 | | 7 | no memoization | 507 | **single complex argument** | Position | Library | Operations per second | | -------- | -------------------------------------------- | --------------------- | | 1 | moize | 27,660,856 | | 2 | memoize-one | 22,407,916 | | 3 | memoizee | 19,546,835 | | 4 | mem (JSON.stringify strategy) | 2,068,038 | | 5 | lodash.memoize (JSON.stringify key resolver) | 1,911,335 | | 6 | fast-memoize | 1,633,855 | | 7 | no memoization | 504 | **multiple primitive arguments** | Position | Library | Operations per second | | -------- | -------------------------------------------- | --------------------- | | 1 | moize | 22,366,497 | | 2 | memoize-one | 17,241,995 | | 3 | memoizee | 9,789,442 | | 4 | mem (JSON.stringify strategy) | 3,065,328 | | 5 | lodash.memoize (JSON.stringify key resolver) | 2,663,599 | | 6 | fast-memoize | 1,219,548 | | 7 | no memoization | 504 | **multiple complex arguments** | Position | Library | Operations per second | | -------- | -------------------------------------------- | --------------------- | | 1 | moize | 21,788,081 | | 2 | memoize-one | 17,321,248 | | 3 | memoizee | 9,595,420 | | 4 | lodash.memoize (JSON.stringify key resolver) | 873,283 | | 5 | mem (JSON.stringify strategy) | 850,779 | | 6 | fast-memoize | 687,863 | | 7 | no memoization | 504 | **multiple complex arguments (spreading arguments)** | Position | Library | Operations per second | | -------- | -------------------------------------------- | --------------------- | | 1 | moize | 21,701,537 | | 2 | memoizee | 19,463,942 | | 3 | memoize-one | 17,027,544 | | 4 | lodash.memoize (JSON.stringify key resolver) | 887,816 | | 5 | mem (JSON.stringify strategy) | 849,244 | | 6 | fast-memoize | 691,512 | | 7 | no memoization | 504 |

## Code health 👍 - Tested with all built in [JavaScript types](https://github.com/getify/You-Dont-Know-JS/blob/1st-ed/types%20%26%20grammar/ch1.md) - Written in `Typescript` - Correct typing for `Typescript` and `flow` type systems - No dependencies package/dist/are-inputs-equal.d.ts000644 0000000160 3560116604 014206 0ustar00000000 000000 export default function areInputsEqual(newInputs: readonly unknown[], lastInputs: readonly unknown[]): boolean; package/src/are-inputs-equal.ts000644 0000002314 3560116604 013613 0ustar00000000 000000 // Number.isNaN as it is not supported in IE11 so conditionally using ponyfill // Using Number.isNaN where possible as it is ~10% faster const safeIsNaN = Number.isNaN || function ponyfill(value: unknown): boolean { // // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/isNaN#polyfill // NaN is the only value in JavaScript which is not equal to itself. return typeof value === 'number' && value !== value; }; function isEqual(first: unknown, second: unknown): boolean { if (first === second) { return true; } // Special case for NaN (NaN !== NaN) if (safeIsNaN(first) && safeIsNaN(second)) { return true; } return false; } export default function areInputsEqual( newInputs: readonly unknown[], lastInputs: readonly unknown[], ): boolean { // no checks needed if the inputs length has changed if (newInputs.length !== lastInputs.length) { return false; } // Using for loop for speed. It generally performs better than array.every // https://github.com/alexreardon/memoize-one/pull/59 for (let i = 0; i < newInputs.length; i++) { if (!isEqual(newInputs[i], lastInputs[i])) { return false; } } return true; } package/dist/memoize-one.d.ts000644 0000001000 3560116604 013230 0ustar00000000 000000 export declare type EqualityFn any> = (newArgs: Parameters, lastArgs: Parameters) => boolean; export declare type MemoizedFn any> = { clear: () => void; (this: ThisParameterType, ...args: Parameters): ReturnType; }; declare function memoizeOne any>(resultFn: TFunc, isEqual?: EqualityFn): MemoizedFn; export default memoizeOne; package/src/memoize-one.ts000644 0000003123 3560116604 012642 0ustar00000000 000000 import areInputsEqual from './are-inputs-equal'; export type EqualityFn any> = ( newArgs: Parameters, lastArgs: Parameters, ) => boolean; export type MemoizedFn any> = { clear: () => void; (this: ThisParameterType, ...args: Parameters): ReturnType; }; // internal type type Cache any> = { lastThis: ThisParameterType; lastArgs: Parameters; lastResult: ReturnType; }; function memoizeOne any>( resultFn: TFunc, isEqual: EqualityFn = areInputsEqual, ): MemoizedFn { let cache: Cache | null = null; // breaking cache when context (this) or arguments change function memoized( this: ThisParameterType, ...newArgs: Parameters ): ReturnType { if (cache && cache.lastThis === this && isEqual(newArgs, cache.lastArgs)) { return cache.lastResult; } // Throwing during an assignment aborts the assignment: https://codepen.io/alexreardon/pen/RYKoaz // Doing the lastResult assignment first so that if it throws // the cache will not be overwritten const lastResult = resultFn.apply(this, newArgs); cache = { lastResult, lastArgs: newArgs, lastThis: this, }; return lastResult; } // Adding the ability to clear the cache of a memoized function memoized.clear = function clear() { cache = null; }; return memoized; } export default memoizeOne;