jest-matcher-utils
Advanced tools
The jest-matcher-utils package provides utility functions for creating custom Jest matchers. It is designed to help developers write their own matchers that integrate seamlessly with Jest's built-in expectation system, offering a way to extend Jest's assertion capabilities with custom logic. The utilities provided by this package include formatting values for error messages, comparing values, and generating matcher error messages.
pretty-format
Formats any JavaScript value for pretty printing, which is useful for generating readable error messages in custom matchers.
const { prettyFormat } = require('jest-matcher-utils');
console.log(prettyFormat({ foo: 'bar' }));matcherHint
Generates a hint string for a matcher, which can be used at the beginning of error messages to indicate which matcher failed.
const { matcherHint } = require('jest-matcher-utils');
console.log(matcherHint('.toBe'));printExpected and printReceived
These functions format the expected and received values to be included in error messages, applying color highlighting to improve readability.
const { printExpected, printReceived } = require('jest-matcher-utils');
console.log(`Expected: ${printExpected(true)}
Received: ${printReceived(false)}`);Chai is a BDD / TDD assertion library for node and the browser that can be delightfully paired with any javascript testing framework. It offers similar functionality to jest-matcher-utils in the sense that it provides a rich set of assertions and plugins to extend its capabilities. However, Chai is a standalone assertion library, not tied to any specific test runner like Jest.
Expect is a minimalist assertion library that comes with Jest but can also be used independently. It provides a similar API for writing test assertions as jest-matcher-utils, but jest-matcher-utils focuses more on the utilities for creating custom matchers rather than providing a comprehensive set of built-in matchers.
24.0.0
[jest-each] [BREAKING] Add primitive pretty printing for interpolated titles (#7694)[jest-runtime] Add jest.isolateModules for scoped module initialization (#6701)[jest-diff] [BREAKING] Support diffing numbers and booleans instead of returning null for different ones (#7605)[jest-diff] [BREAKING] Replace diff with diff-sequences package (#6961)[jest-cli] [BREAKING] Only set error process error codes when they are non-zero (#7363)[jest-config] [BREAKING] Deprecate setupTestFrameworkScriptFile in favor of new setupFilesAfterEnv (#7119)[jest-worker] [BREAKING] Add functionality to call a setup method in the worker before the first call and a teardown method when ending the farm (#7014)[jest-config] [BREAKING] Set default notifyMode to failure-change (#7024)[jest-haste-map] [BREAKING] Remove support for @providesModule (#6104)[jest-haste-map] [BREAKING] Replace internal data structures to improve performance (#6960)[jest-haste-map] [BREAKING] Use relative paths to allow remote caching (#7020)[jest-haste-map] [BREAKING] Remove name from hash in HasteMap.getCacheFilePath (#7218)[babel-preset-jest] [BREAKING] Export a function instead of an object for Babel 7 compatibility (#7203)[jest-haste-map] [BREAKING] Expose relative paths when getting the file iterator (#7321)[jest-cli] [BREAKING] Run code transforms over global{Setup,Teardown} (#7562)[jest-haste-map] Add hasteFS.getSize(path) (#7580)[jest-cli] Print version ending in -dev when running a local Jest clone (#7582)[jest-cli] Add Support for globalSetup and globalTeardown in projects (#6865)[jest-runtime] Add extraGlobals to config to load extra global variables into the execution vm (#7454)[jest-util] Export specialChars containing Unicode characters and ANSI escapes for console output (#7532)[jest-config] Handle typescript (ts and tsx) by default (#7533)[jest-validate] Add support for comments in package.json using a "//" key (#7295)[jest-config] Add shorthand for watch plugins and runners (#7213)[jest-jasmine2/jest-circus/jest-cli] Add test.todo (#6996)[pretty-format] Option to not escape strings in diff messages (#5661)[jest-haste-map] Add getFileIterator to HasteFS for faster file iteration (#7010)[jest-config] Add readConfigs function, previously in jest-cli (#7096)[jest-snapshot] Enable configurable snapshot paths (#6143)[pretty-format] Support HTMLCollection and NodeList in DOMCollection plugin (#7125)[jest-runtime] Pass the normalized configuration to script transformers (#7148)[expect] Improve report when assertion fails, part 3 (#7152)[jest-runtime] If require fails without a file extension, print all files that match with one (#7160)[jest-haste-map] Make ignorePattern optional (#7166)[jest-haste-map] Add getCacheFilePath to get the path to the cache file for a HasteMap instance (#7217)[jest-runtime] Remove cacheDirectory from ignorePattern for HasteMap if not necessary (#7166)[jest-validate] Add syntax to validate multiple permitted types (#7207)[jest-config] Accept an array as as well as a string for testRegex (#7209)[expect/jest-matcher-utils] Improve report when assertion fails, part 4 (#7241)[expect/jest-matcher-utils] Improve report when assertion fails, part 5 (#7557)[expect] Check constructor equality in .toStrictEqual() (#7005)[jest-util] Add jest.getTimerCount() to get the count of scheduled fake timers (#7285)[jest-config] Add dependencyExtractor option to use a custom module to extract dependencies from files (#7313, #7349, #7350, #7362)[jest-haste-map] Accept a getCacheKey method in hasteImplModulePath modules to reset the cache when the logic changes (#7350)[jest-config] Add haste.computeSha1 option to compute the sha-1 of the files in the haste map (#7345)[expect] expect(Infinity).toBeCloseTo(Infinity) Treats Infinity as equal in toBeCloseTo matcher (#7405)[jest-worker] Add node worker-thread support to jest-worker (#7408)[jest-config] Allow bail setting to be configured with a number allowing tests to abort after n of failures (#7335)[jest-config] Allow % based configuration of --max-workers (#7494)[jest-runner] Instantiate the test environment class with the current testPath (#7442)[jest-config] Always resolve jest-environment-jsdom from jest-config (#7476)[expect] Improve report when assertion fails, part 6 (#7621)[jest-worker] Add enableWorkerThreads option to explicitly opt-in to worker_threads if available (#7681)[expect] Accept inherited properties in toHaveProperty matcher (#7686)[jest-diff] Do not claim that -0 and 0 have no visual difference (#7605)[jest-mock] Fix automock for numeric function names (#7653)[jest-config] Ensure existsSync is only called with a string parameter (#7607)[expect] toStrictEqual considers sparseness of arrays. (#7591)[jest-cli] Fix empty coverage data for untested files (#7388)[jest-cli] [BREAKING] Do not use text-summary coverage reporter by default if other reporters are configured (#7058)[jest-mock] [BREAKING] Fix bugs with mock/spy result tracking of recursive functions (#6381)[jest-haste-map] [BREAKING] Recover files correctly after haste name collisions are fixed (#7329)[pretty-format] [BREAKING] Omit non-enumerable symbol properties (#7448)[*] [BREAKING] Upgrade to Babel 7, dropping support for Babel 6 (#7016)[jest-cli] Avoid watch mode causing bad terminal behavior in some cases (#7523)[jest-runner/jest-worker] Fix missing console output in verbose mode (#6871)[expect] Standardize file naming in expect (#7306)[jest-each] Add empty array validation check (#7249)[jest-cli] Interrupt tests if interactive watch plugin key is pressed (#7222)[jest-each] Add each array validation check (#7033)[jest-haste-map] Do not visit again files with the same sha-1 (#6990)[jest-jasmine2] Fix memory leak in Error objects hold by the framework (#6965)[jest-haste-map] Fixed Haste whitelist generation for scoped modules on Windows (#6980)[jest-mock] Fix inheritance of static properties and methods in mocks (#7003)[jest-mock] Fix mocking objects without Object.prototype in their prototype chain (#7003)[jest-mock] Check _isMockFunction is true rather than truthy on potential mocks (#7017)[jest-cli] Update jest-cli to show git ref in message when using changedSince (#7028)[jest-jasmine2] Fix crash when test return Promise rejected with null (#7049)[jest-runtime] Check _isMockFunction is true rather than truthy on potential global mocks (#7017)[jest-jasmine] Show proper error message from async assert errors (#6821)[jest-jasmine2] Better error message when a describe block is empty (#6372)[jest-jasmine2] Pending calls inside async tests are reported as pending not failed (#6782)[jest-circus] Better error message when a describe block is empty (#6372)[jest-jasmine2] Add missing testLocationResults for xit and fit (#6482)[expect] Return false from asymmetric matchers if received value isn’t string (#7107)[jest-cli] Fix unhandled error when a bad revision is provided to changedSince (#7115)[jest-config] Moved dynamically assigned cwd from jest-cli to default configuration in jest-config (#7146)[jest-config] Fix getMaxWorkers on termux (#7154)[jest-runtime] Throw an explicit error if js is missing from moduleFileExtensions (#7160)[jest-runtime] Fix missing coverage when using negative glob pattern in testMatch (#7170)[*] Ensure maxWorkers is at least 1 (was 0 in some cases where there was only 1 CPU) (#7182)[jest-runtime] Fix transform cache invalidation when requiring a test file from multiple projects (#7186)[jest-changed-files] Return correctly the changed files when using lastCommit=true on Mercurial repositories (#7228)[babel-jest] Cache includes babel environment variables (#7239)[jest-config] Use strings instead of RegExp instances in normalized configuration (#7251)[jest-circus] Make sure to display real duration even if time is mocked (#7264)[expect] Improves the failing message for toStrictEqual matcher. (#7224)[expect] Improves the failing message for toEqual matcher. (#7325)[jest-resolve] Fix not being able to resolve path to mapped file with custom platform (#7312)[jest-message-util] Improve parsing of error messages for unusually formatted stack traces (#7319)[jest-runtime] Ensure error message text is not lost on errors with code frames (#7319)[jest-haste-map] Fix to resolve path that is start with words same as rootDir (#7324)[expect] Fix toMatchObject matcher when used with Object.create(null) (#7334)[jest-haste-map] Remove legacy condition for duplicate module detection (#7333)[jest-haste-map] Fix require detection with trailing commas and ignore import typeof modules (#7385)[jest-cli] Fix to set prettierPath via config file (#7412)[expect] Test more precisely for class instance getters (#7477)[jest-cli] Support dashed args (#7497)[jest-cli] Fix to run in band tests if watch mode enable when runInBand arg used (#7518)[jest-runtime] Fix mistake as test files when run coverage issue. (#7506)[jest-cli] print info about passWithNoTests flag (#7309)[pretty-format] Omit unnecessary symbol filter for object keys (#7457)[jest-runtime] Fix requireActual on node_modules with mock present (#7404)[jest-resolve] Fix isBuiltinModule to support versions of node without module.builtinModules (#7565)[babel-jest] Set cwd to be resilient to it changing during the runtime of the tests (#7574)[jest-snapshot] Write and read snapshots from disk even if fs is mocked (#7080)[jest-config] Normalize config.cwd and config.rootDir using `realpath (#7598)[jest-environment-node] Fix buffer property is not ArrayBuffer issue. (#7626)[babel-plugin-jest-hoist] Ignore TS type annotations when looking for out-of-scope references (#7641)[jest-config] Add name to project if one does not exist to pick correct resolver (#5862)[jest-runtime] Pass watchPathIgnorePatterns to Haste instance (#7585)[jest-runtime] Resolve mock files via Haste when using require.resolve (#7687)[*] [BREAKING] Require Node.js 6+ for all packages (#7258)[jest-util] [BREAKING] Remove long-deprecated globals for fake timers (#7285)[*] [BREAKING] Upgrade to Micromatch 3 (#6650)[*] [BREAKING] Remove regenerator-runtime injection (#7595)[jest-worker] Disable worker_threads to avoid issues with libraries to ready for it (#7681)[docs] Fix message property in custom matcher example to return a function instead of a constant. (#7426)[jest-circus] Standardize file naming in jest-circus (#7301)[docs] Add synchronous test.each setup (#7150)[docs] Add this.extend to the Custom Matchers API reference (#7130)[docs] Fix default value for coverageReporters value in configuration docs (#7126)[docs] Add link for jest-extended in expect docs (#7078)[jest-util] Add ErrorWithStack class (#7067)[docs] Document --runTestsByPath CLI parameter (#7046)[docs] Fix babel-core installation instructions (#6745)[docs] Explain how to rewrite assertions to avoid large irrelevant diff (#6971)[examples] add example using Babel 7 (#6983)[docs] Replace shallow equality with referential identity in ExpectAPI.md (#6991)[jest-changed-files] Refactor to use execa over child_process (#6987)[*] Bump dated dependencies (#6978)[scripts] Don’t make empty sub-folders for ignored files in build folder (#7001)[docs] Add missing export statement in puppeteer_environment.js under docs/Puppeteer.md (#7127)[docs] Removed useless expect.assertions in TestingAsyncCode.md (#7131)[docs] Remove references to @providesModule which isn't supported anymore (#7147)[docs] Update setupFiles documentation for clarity (#7187)[docs] Change require.require* to jest.require* (#7210)[jest-circus] Add readme.md (#7198)[jest-editor-support] Remove from the repository (#7232)[jest-test-typescript-parser] Remove from the repository (#7232)[tests] Free tests from the dependency on value of FORCE_COLOR (#6585)[*] Add babel plugin to make sure Jest is unaffected by fake Promise implementations (#7225)[docs] Add correct default value for testUrl config option (#7277)[docs] Remove duplicate code in MockFunctions (#7297)[*] Add check for Facebook copyright headers on CI (#7370)[*] Update Facebook copyright headers (#7589)[jest-haste-map] Refactor dependencyExtractor and tests (#7385)[docs] Clearify conditional setting of NODE_ENV (#7369)[docs] Clarify conditional setting of NODE_ENV (#7369)[*] Standardize file names (#7316, #7266, #7238, #7314, #7467, #7464), #7471)[docs] Add testPathIgnorePatterns in CLI documentation (#7440)[docs] Removed misleading text about describe() grouping together tests into a test suite (#7434)[diff-sequences] Add performance benchmark to package (#7603)[*] Replace as many Object.assign with object spread as possible (#7627)[ci] Initial support for Azure Pipelines (#7556)[jest-mock] Improve getType function performance. (#7159)FAQs
A set of utility functions for expect and related packages
The npm package jest-matcher-utils receives a total of 12,835,882 weekly downloads. As such, jest-matcher-utils popularity was classified as popular.
We found that jest-matcher-utils demonstrated a not healthy version release cadence and project activity because the last version was released a year ago. It has 6 open source maintainers collaborating on the project.
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