jest-haste-map

What is jest-haste-map?

The jest-haste-map npm package is a utility for building a Haste map, which is a mapping from module names to file paths. It is used by Jest to quickly resolve module dependencies for tests by keeping an in-memory map of all available modules. It can handle duplicate module names and provides a way to query the map for a specific module.

What are jest-haste-map's main functionalities?

Building a Haste Map

This code sample demonstrates how to create a new HasteMap instance with a configuration object, build the map, and then use it to get the module name for a specific file.

const HasteMap = require('jest-haste-map');
const config = {
  // These options are required:
  roots: ['/path/to/project'],
  extensions: ['js', 'json'],
  platforms: ['ios', 'android'],
  // You can provide additional options:
  computeSha1: true,
  // other options...
};
const hasteMap = new HasteMap(config);
hasteMap.build().then(map => {
  console.log(map.hasteFS.getModuleName('/path/to/project/file.js'));
});

Querying the Haste Map

This code sample shows how to query the built Haste map for the path of a module given its name, platform, and whether it supports the native platform.

hasteMap.build().then(map => {
  const modulePath = map.moduleMap.getModule('moduleName', 'platform', 'supportsNativePlatform');
  console.log(modulePath);
});

Other packages similar to jest-haste-map

metro

Metro is a JavaScript bundler for React Native applications. It includes a Haste map implementation similar to jest-haste-map, but it is tailored specifically for React Native and includes additional features for bundling and transforming code.

webpack

Webpack is a powerful module bundler for JavaScript applications. While it does not use a Haste map, it provides a similar functionality through its own resolution mechanism, which can handle complex dependency graphs and offers a wide range of plugins for different tasks.

browserify

Browserify is a tool for bundling JavaScript files for usage in the browser. Like webpack, it does not use a Haste map, but it allows developers to require modules in the browser by bundling up all dependencies. It's simpler than webpack and may be more suitable for smaller projects.

README

The README file is missing

Changelog

29.7.0

Features

• [create-jest] Add npm init / yarn create initialiser for Jest projects (#14465)
• [jest-validate] Allow deprecation warnings for unknown options (#14499)

Fixes

• [jest-resolver] Replace unmatched capture groups in moduleNameMapper with empty string instead of undefined (#14507)
• [jest-snapshot] Allow for strings as well as template literals in inline snapshots (#14465)
• [@jest/test-sequencer] Calculate test runtime if perStats.duration is missing (#14473)

Performance

• [@jest/create-cache-key-function] Cache access of NODE_ENV and BABEL_ENV (#14455)

Chore & Maintenance

• [jest-cli] Move internal config initialisation logic to the create-jest package (#14465)