jest-cli

library30.3.0jsnpmunverified

Jest is a popular and delightful JavaScript testing framework known for its focus on simplicity, performance, and features like snapshot testing and built-in mocking. It offers a powerful command-line interface (CLI) to run tests, generate coverage reports, and interact with the test runner. The current stable version is 30.3.0, released after a significant three-year development cycle for version 30.0.0, with a stated aim for more frequent major releases going forward. Jest differentiates itself with an 'all-in-one' approach, providing an assertion library, test runner, and mocking capabilities out of the box, often requiring minimal configuration for many projects. It supports TypeScript out-of-the-box and is widely adopted across various JavaScript environments, including Node.js, React, Angular, and Vue projects.

testing

npm install jest-cli

github ↗package ↗homepage ↗

INSTALL

IMPORT

SIG · JEST-CLI

jest-cli

testingjavascriptv30.3.0

Install

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Import

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Disk

—

Pass rate

0/ 6

Env Coverage0 / 6

glibc

18–22

musl

18–22

Install & Compatibility

Where this runs

tested against v? · npm install

Install × environment matrix

Each cell = how many times install + import succeeded across repeated harness runs. Partial = flaky.
glibc = Debian/Ubuntu slim · musl = Alpine Linux

musl

node 18–226 runs

build_error

glibc

node 18–226 runs

build_error

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

defineConfig

✓ import { defineConfig } from 'jest-config';

✗ const config = require('jest-config').defineConfig;

Introduced in Jest 30.3.0 for type-safe configuration files (e.g., jest.config.ts). This is the recommended way to define Jest configurations when using TypeScript or ESM.

jest

✓ import { jest } from '@jest/globals';

✗ import jest from 'jest'; // This imports the CLI, not the globals

While `jest` is often available globally in test environments, explicitly importing from `@jest/globals` is recommended for better type safety and clarity, especially in ESM projects or when `globals: false` is set in config.

expect

✓ import { expect } from '@jest/globals';

✗ import { expect } from 'jest-expect'; // Not the primary way

Similar to `jest`, `expect` is typically available globally. Explicitly importing from `@jest/globals` ensures type inference and is good practice, especially when `globals: false` is configured.

Demonstrates basic Jest test structure using `describe`, `test`, and `expect` with TypeScript, along with setup instructions for a minimal Jest project.

import { describe, expect, test } from '@jest/globals'; function sum(a: number, b: number): number { return a + b; } describe('sum module', () => { test('adds 1 + 2 to equal 3', () => { expect(sum(1, 2)).toBe(3); }); test('object assignment', () => { const data = { one: 1 }; data['two'] = 2; expect(data).toEqual({ one: 1, two: 2 }); }); test('null', () => { const n = null; expect(n).toBeNull(); expect(n).toBeDefined(); expect(n).not.toBeUndefined(); expect(n).not.toBeTruthy(); expect(n).toBeFalsy(); }); test('truthy or falsy', () => { const z = 0; const a = 1; expect(z).not.toBeTruthy(); expect(a).toBeTruthy(); expect(z).toBeFalsy(); }); }); // To run this test: // 1. Install Jest: npm install --save-dev jest typescript ts-jest @types/jest // 2. Create a jest.config.ts: // import { defineConfig } from 'jest-config'; // export default defineConfig({ // preset: 'ts-jest', // testEnvironment: 'node', // }); // 3. Add to package.json scripts: "test": "jest" // 4. Run: npm test

jest --version

Debug

Known issues

breakingJest 30 is a major release with significant internal refactors and changes. While many tests might work without modification, a migration guide is provided, and specific behaviors related to resolvers, runners, and environments may have changed. Always consult the official migration guide when upgrading from Jest 29 or earlier.

fix

Review the official Jest 30 migration guide (jestjs.io/docs/upgrading-to-jest30) and adapt test files, configurations, and dependencies as needed. Pay close attention to changes in custom resolvers, environments, or reporters.

affects: >=30.0.0

breakingNode.js version requirements have been updated. Jest 30 now requires Node.js version 18.14.0 or higher. Running Jest with older Node.js versions will result in errors.

fix

Upgrade your Node.js environment to version 18.14.0, 20.x, 22.x, 24.x or later. Use a tool like `nvm` to manage Node.js versions if necessary.

affects: >=30.0.0

deprecatedThe `jest-runtime` package no longer supports `new Script` and now uses `compileFunction`. While largely an internal change, this might affect projects that heavily customized module loading or relied on specific `new Script` behaviors within their Jest environment.

fix

Most users will not need to do anything. If you have highly customized test environments or module loading, verify that your setup still functions correctly. If issues arise, consult the Jest documentation on custom environments or module resolution.

affects: >=30.0.0-beta.4

gotchaJest's globals (`jest`, `expect`, `test`, `describe` etc.) are enabled by default. If you use ESM or TypeScript and prefer explicit imports for better module hygiene and type inference, you might encounter 'is not defined' errors when `globals: false` is set in your config.

fix

Explicitly import globals: `import { test, expect, describe } from '@jest/globals';` in each test file. Alternatively, ensure `globals: true` is set in your Jest configuration file.

affects: >=27.0.0

Errors

Common errors & fixes

ReferenceError: test is not defined

Jest's test globals are not available in the current scope. This typically happens if `globals: false` is configured in `jest.config.js` or if you are trying to run a test file without Jest's environment.

fix

Add `import { test, expect, describe } from '@jest/globals';` at the top of your test file, or ensure `globals: true` is set in your Jest configuration file.

SyntaxError: Cannot use import statement outside a module

This error occurs when Jest tries to process an ES module using CommonJS resolution rules, or vice versa, often due to misconfiguration of `type: 'module'` in `package.json` or incorrect `jest.config.js` settings for module resolution.

fix

Ensure your `jest.config.js` is correctly configured for your project's module system. If your project is ESM, ensure `type: 'module'` in `package.json` and use `jest.config.mjs` or `jest.config.ts` with `defineConfig`. If CJS, use `jest.config.js` and consider `transform` options for ESM imports.

Your test suite must contain at least one test. (no tests found)

Jest couldn't find any test files matching its `testMatch` or `testRegex` configuration, or the test files themselves do not contain any `test` or `it` blocks.

fix

Verify your `jest.config.js` `testMatch` or `testRegex` patterns are correct (e.g., `**/*.test.ts`, `**/*.spec.js`). Ensure your test files contain actual test definitions using `test('description', () => {...})` or `it('description', () => {...})`.

Upgrade

Version history

30.3.0latest on npm

Audit

Dependencies

node-notifieroptionalUsed for desktop notifications when tests pass or fail, providing immediate feedback.

Agent activity

6 hits · last 30 days

node

Resources

githubhttps://github.com/jestjs/jest ↗

packagehttps://www.npmjs.com/package/jest-cli ↗

homepagehttps://jestjs.io ↗