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

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)