# jest-haste-map > `jest-haste-map` is a module used by Jest, a popular JavaScript testing framework, to create a fast lookup of files in a project. It helps Jest efficiently locate and track changes in files during testing, making it particularly useful for large projects Latest version **30.5.1** (published 2026-09-01) · MIT license · 0 weekly downloads ## Install ```sh npm install jest-haste-map pnpm add jest-haste-map yarn add jest-haste-map bun add jest-haste-map ``` ## Health **Score 70/100 (B)** — status: active. Positive: has types; esm support; no vulnerabilities; recently updated; high maintenance score; popular repo. Warnings: low downloads. ## Facts | | | |---|---| | Version | 30.5.1 | | Published | 2026-09-01 | | First published | 2016-04-14 | | Weekly downloads | 0 | | License | MIT | | TypeScript types | bundled | | Module format | ESM + CommonJS | | Node | ^18.14.0 \|\| ^20.0.0 \|\| ^22.0.0 \|\| >=24.0.0 | | Dependencies | 11 | | Unpacked size | 155.7 KB | | Known vulnerabilities | 0 | | Install scripts | no | | GitHub stars | 45465 | | Maintainers | aaronabramov, simenb, rickhanlonii, openjs-operations, cpojer | ## Links - npm: https://www.npmjs.com/package/jest-haste-map - Repository: https://github.com/jestjs/jest - Homepage: https://github.com/jestjs/jest#readme - Issues: https://github.com/jestjs/jest/issues - npm.io page: https://npm.io/package/jest-haste-map ## Dependencies (11) - [fdir](https://npm.io/package/fdir.md) ^6.5.0 - [anymatch](https://npm.io/package/anymatch.md) ^3.1.3 - [jest-util](https://npm.io/package/jest-util.md) 30.5.1 - [picomatch](https://npm.io/package/picomatch.md) ^4.0.3 - [@jest/types](https://npm.io/package/@jest/types.md) 30.5.1 - [@types/node](https://npm.io/package/@types/node.md) * - [fb-watchman](https://npm.io/package/fb-watchman.md) ^2.0.2 - [graceful-fs](https://npm.io/package/graceful-fs.md) ^4.2.11 - [jest-worker](https://npm.io/package/jest-worker.md) 30.5.1 - [@parcel/watcher](https://npm.io/package/@parcel/watcher.md) ^2.6.0 - [jest-regex-util](https://npm.io/package/jest-regex-util.md) 30.5.0 ## Recent versions - 30.5.1 (latest) — 2026-09-01 - 30.0.0-rc.1 (next) — 2025-06-09 - 20.0.5 (alpha) — 2017-07-17 - 30.5.0 — 2026-08-28 - 30.4.1 — 2026-05-08 - 30.4.0 — 2026-05-07 - 30.3.0 — 2026-03-10 - 30.2.0 — 2025-09-28 - 30.1.0 — 2025-08-27 - 30.0.5 — 2025-07-22 - 30.0.2 — 2025-06-19 - 30.0.1 — 2025-06-18 - 30.0.0 — 2025-06-10 - 30.0.0-beta.8 — 2025-06-04 - 30.0.0-beta.7 — 2025-06-04 - … 278 more at https://npm.io/package/jest-haste-map/versions ## README # jest-haste-map `jest-haste-map` is a module used by Jest, a popular JavaScript testing framework, to create a fast lookup of files in a project. It helps Jest efficiently locate and track changes in files during testing, making it particularly useful for large projects with many files. ## why jest-haste-map ? - **Parallel crawling and analysis:** jest-haste-map crawls the entire project, extracts dependencies, and analyzes files in parallel across worker processes.This can significantly improve the performance of the map building process. - **Cached file system:** jest-haste-map keeps a cache of the file system in memory and on disk. This allows for fast file related operations, such as resolving module imports and checking for changes. - **Minimal work**: jest-haste-map only does the minimal amount of work necessary when files change. When using [watchman](https://facebook.github.io/watchman/) (recommended for large projects), Jest asks watchman for changed files instead of crawling the file system. Without watchman, [@parcel/watcher](https://github.com/parcel-bundler/watcher) is used — it picks the best native backend for the platform (`fs-events` on macOS, `inotify` on Linux, `windows` on Windows). - **File system watching:** jest-haste-map can watch the file system for changes. This is useful for building interactive tools, such as watch mode. ## Installation with npm : ```bash npm install jest-haste-map --save-dev ``` with yarn : ```bash yarn add jest-haste-map --dev ``` ## usage `jest-haste-map` is compatible with both `ES modules` and `CommonJS` ### simple usage ```javascript const map = new HasteMap.default({ // options }); ``` ### Example usage (get all files with .js extension in the project) ```javascript import HasteMap from 'jest-haste-map'; import os from 'os'; import {dirname} from 'path'; import {fileURLToPath} from 'url'; const root = dirname(fileURLToPath(import.meta.url)); const map = new HasteMap.default({ id: 'myproject', //Used for caching. extensions: ['js'], // Tells jest-haste-map to only crawl .js files. maxWorkers: os.availableParallelism(), //Parallelizes across all available CPUs. platforms: [], // This is only used for React Native, you can leave it empty. roots: [root], // Can be used to only search a subset of files within `rootDir` retainAllFiles: true, rootDir: root, //The project root. }); const {hasteFS} = await map.build(); const files = hasteFS.getAllFiles(); console.log(files); ``` ### options | Option | Type | Required | Default Value | | ---------------------- | ------------------- | -------- | ------------- | | cacheDirectory | string | No | `os.tmpdir()` | | computeDependencies | boolean | No | `true` | | computeSha1 | boolean | No | `false` | | console | Console | No | - | | dependencyExtractor | string \| null | No | `null` | | enableSymlinks | boolean | No | `false` | | extensions | Array<string> | Yes | - | | forceNodeFilesystemAPI | boolean | No | `false` | | hasteImplModulePath | string | No | - | | hasteMapModulePath | string | No | - | | id | string | Yes | - | | ignorePattern | HasteRegExp | No | - | | maxWorkers | number | Yes | - | | mocksPattern | string | No | - | | platforms | Array<string> | Yes | - | | resetCache | boolean | No | - | | retainAllFiles | boolean | Yes | - | | rootDir | string | Yes | - | | roots | Array<string> | Yes | - | | skipPackageJson | boolean | No | `false` | | throwOnModuleCollision | boolean | No | `false` | | useWatchman | boolean | No | `true` | For more, you can check [github](https://github.com/jestjs/jest/tree/main/packages/jest-haste-map) --- _Source: https://npm.io/package/jest-haste-map · Machine-readable twin of the npm.io package page. 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