jest-resolve

What is jest-resolve?

The jest-resolve package is a module resolver used by Jest, the JavaScript testing framework. It resolves the location of modules in your project, allowing Jest to hook into the module resolution logic. This is particularly useful for mocking modules or creating custom resolution logic for tests.

What are jest-resolve's main functionalities?

Resolving modules

This feature allows you to resolve the path to a module within your project. You can specify directories and file extensions to consider during resolution.

const Resolver = require('jest-resolve');
const resolver = new Resolver({}, {
  moduleDirectory: ['node_modules'],
  extensions: ['.js', '.json', '.jsx', '.ts', '.tsx', '.node']
});
const resolvedPath = resolver.resolveModule('/path/to/project', 'module-name');

Creating a custom resolver

This feature enables you to create a custom resolver function that can be used by Jest to resolve modules according to your specific needs.

const Resolver = require('jest-resolve');
const customResolver = (request, options) => {
  // Custom resolution logic here
  return Resolver.findNodeModule(request, options);
};

Other packages similar to jest-resolve

resolve

The 'resolve' package is a module resolution library that can be used independently of any test framework. It provides similar functionality to jest-resolve but is not tied to Jest. It's more generic and can be used in a variety of different projects.

enhanced-resolve

This package is used internally by webpack for module resolution. It offers a highly configurable resolution mechanism that can handle complex scenarios like resolving modules based on file system state or package descriptions. It's more powerful than jest-resolve but also more complex to configure.

browser-resolve

browser-resolve is a resolver for browser-based modules. It's similar to jest-resolve but focuses on resolving modules in a way that's compatible with the browser environment, taking into account the browser field in package.json files.

README

The README file is missing

Changelog

23.6.0

Features

• [jest-cli] Add changedSince to allowed watch mode configs (#6955)
• [babel-jest] Add support for babel.config.js added in Babel 7.0.0 (#6911)
• [jest-resolve] Add support for an experimental mapper option (Watchman crawler only) that adds virtual files to the Haste map (#6940)

Fixes

• [jest-resolve] Only resolve realpath once in try-catch (#6925)
• [expect] Fix TypeError in toBeInstanceOf on null or undefined (#6912)
• [jest-jasmine2] Throw a descriptive error if the first argument supplied to a hook was not a function (#6917) and (#6931)
• [jest-circus] Throw a descriptive error if the first argument supplied to a hook was not a function (#6917) and (#6931)
• [expect] Fix variadic custom asymmetric matchers (#6898)
• [jest-cli] Fix incorrect testEnvironmentOptions warning (#6852)
• [jest-each] Prevent done callback being supplied to describe (#6843)
• [jest-config] Better error message for a case when a preset module was found, but no jest-preset.js or jest-preset.json at the root (#6863)
• [jest-haste-map] Catch crawler error when unsuccessfully reading directories (#6761)

Chore & Maintenance

• [docs] Add custom toMatchSnapshot matcher docs (#6837)
• [docs] Improve the documentation regarding preset configuration (#6864)
• [docs] Clarify usage of --projects CLI option (#6872)
• [docs] Correct failure-change notification mode (#6878)
• [scripts] Don’t remove node_modules from subdirectories of presets in e2e tests (#6948)
• [diff-sequences] Double-check number of differences in tests (#6953)