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

jest 15.0.0

• See https://jestjs.io/blog/2016/09/01/jest-15
• Jest by default now also recognizes files ending in .spec.js and .test.js as test files.
• Completely replaced most Jasmine matchers with new Jest matchers.
• Rewrote Jest's CLI output for test failures and summaries.
• Added --env option to override the default test environment.
• Disabled automocking, fake timers and resetting the module registry by default.
• Added --watchAll, made --watch interactive and added the ability to update snapshots and select test patterns in watch mode.
• Jest uses verbose mode when running a single test file.
• Console messages are now buffered and printed along with the test results.
• Fix testEnvironment resolution to prefer jest-environment-{name} instead of {name} only. This prevents a module collision when using jsdom as test environment.
• moduleNameMapper now uses a resolution algorithm.
• Improved performance for small test runs.
• Improved API documentation.
• Jest now works properly with directories that have special characters in them.
• Improvements to Jest's own test infra by merging integration and unit tests. Code coverage is now collected for Jest.
• Added global.global to the node environment.
• Fixed babel-jest-plugin-hoist issues with functions called mock.
• Improved jest-react-native preset with mocks for ListView, TextInput, ActivityIndicator and ScrollView.
• Added collectCoverageFrom to collect code coverage from untested files.
• Rewritten code coverage support.