├── package.json ├── src ├── index.js └── benchmarks.js ├── LICENSE ├── .gitignore ├── README.md └── results ├── reduce.svg └── map.svg /package.json: -------------------------------------------------------------------------------- 1 | { 2 | "name": "js-array-performance", 3 | "version": "1.0.0", 4 | "description": "Performance benchmarks of different array iteration methods", 5 | "main": "src/index.js", 6 | "scripts": { 7 | "start": "node src/index.js" 8 | }, 9 | "repository": { 10 | "type": "git", 11 | "url": "git+https://github.com/LeanyLabs/js-array-performance.git" 12 | }, 13 | "keywords": [ 14 | "array", 15 | "performance", 16 | "javascript" 17 | ], 18 | "author": "LeanyLabs", 19 | "license": "MIT", 20 | "bugs": { 21 | "url": "https://github.com/LeanyLabs/js-array-performance/issues" 22 | }, 23 | "homepage": "https://github.com/LeanyLabs/js-array-performance#readme", 24 | "dependencies": { 25 | "benchmark": "^2.1.4" 26 | } 27 | } 28 | -------------------------------------------------------------------------------- /src/index.js: -------------------------------------------------------------------------------- 1 | const { 2 | buildForEachSuite, 3 | buildMapSuite, 4 | buildReduceSuite, 5 | } = require("./benchmarks"); 6 | 7 | function runSuite(suite) { 8 | console.log(`\nBenchmarking ${suite.name}:`); 9 | 10 | suite 11 | .on("cycle", function (event) { 12 | console.log(String(event.target)); 13 | }) 14 | .on("complete", function () { 15 | console.log(this.filter("fastest").map("name") + " is faster"); 16 | }) 17 | .run(); 18 | } 19 | 20 | function generateTestArray() { 21 | const result = []; 22 | for (let i = 0; i < 1000000; ++i) { 23 | result.push({ 24 | a: i, 25 | b: i / 2, 26 | r: 0, 27 | }); 28 | } 29 | return result; 30 | } 31 | 32 | const testArray = generateTestArray(); 33 | 34 | runSuite(buildForEachSuite(testArray)); 35 | runSuite(buildMapSuite(testArray)); 36 | runSuite(buildReduceSuite(testArray)); 37 | -------------------------------------------------------------------------------- /LICENSE: -------------------------------------------------------------------------------- 1 | MIT License 2 | 3 | Copyright (c) 2021 LeanyLabs 4 | 5 | Permission is hereby granted, free of charge, to any person obtaining a copy 6 | of this software and associated documentation files (the "Software"), to deal 7 | in the Software without restriction, including without limitation the rights 8 | to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 9 | copies of the Software, and to permit persons to whom the Software is 10 | furnished to do so, subject to the following conditions: 11 | 12 | The above copyright notice and this permission notice shall be included in all 13 | copies or substantial portions of the Software. 14 | 15 | THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 16 | IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 17 | FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 18 | AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 19 | LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 20 | OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE 21 | SOFTWARE. 22 | -------------------------------------------------------------------------------- /.gitignore: -------------------------------------------------------------------------------- 1 | # Logs 2 | logs 3 | *.log 4 | npm-debug.log* 5 | yarn-debug.log* 6 | yarn-error.log* 7 | lerna-debug.log* 8 | 9 | # Diagnostic reports (https://nodejs.org/api/report.html) 10 | report.[0-9]*.[0-9]*.[0-9]*.[0-9]*.json 11 | 12 | # Runtime data 13 | pids 14 | *.pid 15 | *.seed 16 | *.pid.lock 17 | 18 | # Directory for instrumented libs generated by jscoverage/JSCover 19 | lib-cov 20 | 21 | # Coverage directory used by tools like istanbul 22 | coverage 23 | *.lcov 24 | 25 | # nyc test coverage 26 | .nyc_output 27 | 28 | # Grunt intermediate storage (https://gruntjs.com/creating-plugins#storing-task-files) 29 | .grunt 30 | 31 | # Bower dependency directory (https://bower.io/) 32 | bower_components 33 | 34 | # node-waf configuration 35 | .lock-wscript 36 | 37 | # Compiled binary addons (https://nodejs.org/api/addons.html) 38 | build/Release 39 | 40 | # Dependency directories 41 | node_modules/ 42 | jspm_packages/ 43 | 44 | # TypeScript v1 declaration files 45 | typings/ 46 | 47 | # TypeScript cache 48 | *.tsbuildinfo 49 | 50 | # Optional npm cache directory 51 | .npm 52 | 53 | # Optional eslint cache 54 | .eslintcache 55 | 56 | # Microbundle cache 57 | .rpt2_cache/ 58 | .rts2_cache_cjs/ 59 | .rts2_cache_es/ 60 | .rts2_cache_umd/ 61 | 62 | # Optional REPL history 63 | .node_repl_history 64 | 65 | # Output of 'npm pack' 66 | *.tgz 67 | 68 | # Yarn Integrity file 69 | .yarn-integrity 70 | 71 | # dotenv environment variables file 72 | .env 73 | .env.test 74 | 75 | # parcel-bundler cache (https://parceljs.org/) 76 | .cache 77 | 78 | # Next.js build output 79 | .next 80 | 81 | # Nuxt.js build / generate output 82 | .nuxt 83 | dist 84 | 85 | # Gatsby files 86 | .cache/ 87 | # Comment in the public line in if your project uses Gatsby and *not* Next.js 88 | # https://nextjs.org/blog/next-9-1#public-directory-support 89 | # public 90 | 91 | # vuepress build output 92 | .vuepress/dist 93 | 94 | # Serverless directories 95 | .serverless/ 96 | 97 | # FuseBox cache 98 | .fusebox/ 99 | 100 | # DynamoDB Local files 101 | .dynamodb/ 102 | 103 | # TernJS port file 104 | .tern-port 105 | -------------------------------------------------------------------------------- /README.md: -------------------------------------------------------------------------------- 1 | # Performance benchmarks for different array iteration methods. 2 | 3 | The goal is to show that imperative programming using `for` and `for...of` is 3+ times faster than declarative alternatives. 4 | 5 | In most cases, when dealing with small arrays, this doesn't matter and won't affect the whole application's performance in any way. However, when processing large amounts of data in some kind of business intelligence app, video processing, scientific calculations, or game engine, this will have a massive effect on the overall performance. 6 | 7 | Running the tests locally: 8 | 9 | ```bash 10 | npm i 11 | npm start 12 | ``` 13 | 14 | ## Results on i7-13700H running Ubuntu 22.04 LTS with Node v22.3.0 15 | 16 | ![forEach vs for vs for..of](results/forEach.svg) 17 | ![map vs for vs for..of](results/map.svg) 18 | ![reduce vs for vs for..of](results/reduce.svg) 19 | 20 | ``` 21 | Benchmarking forEach: 22 | Array.forEach x 221 ops/sec ±5.37% (85 runs sampled) 23 | for of x 205 ops/sec ±6.49% (84 runs sampled) 24 | for { 7 | x.r = x.a + x.b; 8 | }); 9 | }) 10 | .add("for of", function () { 11 | for (const obj of array) { 12 | obj.r = obj.a + obj.b; 13 | } 14 | }) 15 | .add("for x.a + x.b); 45 | }) 46 | .add("Array.map, destructuring", function () { 47 | return array.map(({ a, b }) => a + b); 48 | }) 49 | .add("for of", function () { 50 | const result = []; 51 | for (const obj of array) { 52 | result.push(obj.a + obj.b); 53 | } 54 | return result; 55 | }) 56 | .add("for of, destructuring", function () { 57 | const result = []; 58 | for (const { a, b } of array) { 59 | result.push(a + b); 60 | } 61 | return result; 62 | }) 63 | .add("for, init array", function () { 64 | const result = new Array(array.length); 65 | for (let i = 0; i < array.length; ++i) { 66 | result[i] = array[i].a + array[i].b; 67 | } 68 | return result; 69 | }); 70 | } 71 | 72 | function buildReduceSuite(array) { 73 | return new Benchmark.Suite("reduce") 74 | .add("Array.reduce", function () { 75 | return array.reduce((p, x) => p + x.a + x.b, 0); 76 | }) 77 | .add("Array.reduce, destructuring", function () { 78 | return array.reduce((p, { a, b }) => p + a + b, 0); 79 | }) 80 | .add("for of", function () { 81 | let result = 0; 82 | for (const { a, b } of array) { 83 | result += a + b; 84 | } 85 | return result; 86 | }) 87 | .add("for", function () { 88 | let result = 0; 89 | for (let i = 0; i < array.length; ++i) { 90 | result += array[i].a + array[i].b; 91 | } 92 | return result; 93 | }); 94 | } 95 | 96 | module.exports = { 97 | buildReduceSuite, 98 | buildForEachSuite, 99 | buildMapSuite, 100 | }; 101 | -------------------------------------------------------------------------------- /results/reduce.svg: -------------------------------------------------------------------------------- 1 | -------------------------------------------------------------------------------- /results/map.svg: -------------------------------------------------------------------------------- 1 | --------------------------------------------------------------------------------