jest-util

What is jest-util?

The jest-util package provides utility functions for Jest, a popular JavaScript testing framework. It includes a variety of helpers and tools that are used internally by Jest but can also be useful for developers working with or extending Jest tests.

What are jest-util's main functionalities?

Console Replacement

This feature allows for the creation of a custom console that buffers all logs. This is useful for controlling and testing console output during test runs.

const { BufferedConsole } = require('jest-util');
const customConsole = new BufferedConsole();
customConsole.log('Hello, this is a buffered log.');

Error Formatting

This function formats execution errors for display in Jest's output, providing a standardized view of test errors, including stack traces.

const { formatExecError } = require('jest-util');
const error = new Error('Test error');
const config = {rootDir: '/path/to/project', testMatch: []};
console.log(formatExecError(error, config, {noStackTrace: false}, undefined, true));

Test Path Normalization

This utility normalizes file paths for glob matching, which is particularly useful on Windows where path separators differ.

const { replacePathSepForGlob } = require('jest-util');
const path = 'path\to\test\file.js';
console.log(replacePathSepForGlob(path));

Other packages similar to jest-util

chai

Chai is an assertion library similar to jest-util in that it is used to help with testing JavaScript applications. Unlike jest-util, Chai focuses more on providing a rich set of assertions rather than utilities for managing Jest environments or outputs.

mocha

Mocha is a test framework that, like Jest, can utilize utility packages for enhanced testing capabilities. While jest-util specifically supports Jest, Mocha has its own set of utilities and plugins that serve a similar purpose but are tailored to Mocha's ecosystem.

sinon

Sinon provides standalone test spies, stubs, and mocks for JavaScript. It complements jest-util by offering more focused functionalities for creating and managing test doubles, which can be used alongside or independently of Jest.

README

The README file is missing

Changelog

26.1.0

Features

• [jest-mock] Export Mock, MockInstance, SpyInstance types (#10138)
• [jest-config] Support config files exporting (async) functions (#10001)
• [jest-cli, jest-core] Add --selectProjects CLI argument to filter test suites by project name (#8612)
• [jest-cli, jest-init] Add coverageProvider to jest --init prompts (#10044)

Fixes

• [jest-console] getConsoleOutput to receive global stack trace config and use it to format stack trace (#10081)
• [jest-jasmine2] Stop adding : after an error that has no message (#9990)
• [jest-diff] Control no diff message color with commonColor in diff options (#9997)
• [jest-snapshot] Fix TypeScript compilation (#10008)

Chore & Maintenance

• [docs] Correct confusing filename in enableAutomock example (#10055)
• [jest-core] 🎉🎉🎉🎉🎉🎉🎉🎉🎉🎉🎉🎉🎉🎉🎉🎉🎉🎉🎉🎉🎉🎉🎉🎉🎉 (#10000)
• [jest-core, jest-reporters, jest-test-result, jest-types] Cleanup displayName type (#10049)
• [jest-runtime] Jest-internal sandbox escape hatch (#9907)
• [jest-fake-timers] Update now param type to support Date in addition to number. (#10169)
• [docs] Add param to setSystemTime docs and remove preceding period from it and getRealSystemTime (#10169)
• [jest-snapshot, jest-util] Replace make-dir with fs.mkdir (#10136)
• [docs] Added parcel-bundler documentation inside readme.md file

Performance

• [jest-core, jest-transform, jest-haste-map] Improve Jest startup time and test runtime, particularly when running with coverage, by caching micromatch and avoiding recreating RegExp instances (#10131)