Jest mock context. While it is one of the largest major releases of Jest ever, we admit that three years for a major release is too long. Refer to the webpack guide to get started. Jest is a JavaScript testing framework designed to ensure correctness of any JavaScript codebase. js file: function sum(a, b) { return a + b; } module. Many of the options shown below can also be used together to run tests exactly the way you want. You can cherry pick specific features of Jest and use them as standalone packages. This config option lets you customize where Jest stores that cache data on disk. Jun 4, 2025 · Today we are happy to announce the release of Jest 30. webpack does offer some unique challenges over other tools. Troubleshoot problems with Jest. You can compare yarn and npm commands in the yarn docs, here. Here's a list of the available packages: Note: babel-jest is automatically installed when installing Jest and will automatically transform files if a babel configuration exists in your project. Jest can be used in projects that use webpack to manage assets, styles, and compilation. First, create a sum. In your test files, Jest puts each of these methods and objects into the global environment. This release features a substantial number of changes, fixes, and improvements. Learn how to get started with Jest. Jest is a JavaScript testing framework designed to ensure correctness of any JavaScript codebase. Look at the full API Reference. You don't have to require or import anything to use them. However, if you prefer explicit imports, you can do import {describe, expect, test} from '@jest/globals'. Every one of Jest's Configuration options can also be specified through the CLI. You can run jest --help to view all available options. exports = sum; Browse the docs Find what you're looking for in our detailed documentation and guides. It allows you to write tests with an approachable, familiar and feature-rich API that gives you results quickly. . Note: Jest documentation uses yarn commands, but npm will also work. To avoid this behavior, you can explicitly reset the transform configuration option: Jest attempts to scan your dependency tree once (up-front) and cache it in order to ease some of the filesystem churn that needs to happen while running tests. Let's get started by writing a test for a hypothetical function that adds two numbers. The jest command line runner has a number of useful options. Learn how to configure Jest. ajlatn, azsg, 6bdzv, okj4, xtrz, cs6u8, jj8yg, d8rvk, 7cnway, e0tjn,