@nrwl/jest

What is @nrwl/jest?

The @nrwl/jest package is part of the Nx suite of tools, designed to enhance the development experience with Jest in a monorepo setup. It provides seamless integration of Jest into Nx workspaces, enabling efficient unit testing configurations, execution, and optimizations tailored for projects managed within an Nx workspace.

What are @nrwl/jest's main functionalities?

Simplified Jest Configuration

Allows for simplified and centralized Jest configuration within an Nx workspace, making it easier to manage and share configurations across multiple library and application projects.

{
  "jestConfig": "./jest.config.js",
  "tsConfig": "./tsconfig.spec.json",
  "setupFile": "./src/test-setup.ts"
}

Parallel Test Execution

Enables parallel execution of tests across multiple projects within the workspace, significantly reducing the total time required for running tests in large projects.

nx run-many --target=test --all --parallel

Test Affected Projects

Identifies and runs tests only for the projects affected by recent changes, improving efficiency in continuous integration pipelines by skipping tests for unchanged projects.

nx affected:test

Other packages similar to @nrwl/jest

jest

Jest is the underlying testing framework that @nrwl/jest configures and enhances for use within Nx workspaces. While Jest can be used independently for testing JavaScript and TypeScript projects, @nrwl/jest provides additional integrations and optimizations for monorepo setups.

mocha

Mocha is another popular JavaScript test framework that can be used for unit and integration testing. Unlike @nrwl/jest, which is tailored for Jest and Nx workspaces, Mocha offers a more general-purpose testing solution without specific optimizations for monorepos or Nx.

karma

Karma is a test runner developed by the AngularJS team, designed to work with any framework. It differs from @nrwl/jest by focusing on executing tests in real browsers, providing a more integrated environment for testing browser-specific features. However, it lacks the monorepo-specific enhancements provided by @nrwl/jest.

README

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What is Nx?

🔎 Extensible Dev Tools for Monorepos.

Nx Helps You

Use Modern Tools

Using Nx, you can add TypeScript, Cypress, Jest, Prettier, and Nest into your dev workflow. Nx sets up these tools and allows you to use them seamlessly. Nx fully integrates with the other modern tools you already use and love.

Build Full-Stack Applications

With Nx, you can build full-stack applications using modern frameworks. You can share code between the frontend and the backend. And you can use the same build/test/serve commands throughout the whole dev experience.

Develop like Google, Facebook, and Microsoft

With Nx, you can develop multiple full-stack applications holistically and share code between them all in the same workspace. Nx provides advanced tools which help you scale your enterprise development. Nx also helps enforce your organization’s standards and community best practices.

Getting Started

Creating an Nx Workspace

Using npx

npx create-nx-workspace myworkspace

Using npm init

npm init nx-workspace myworkspace

Using yarn create

yarn create nx-workspace myworkspace

If it's your first Nx project, the command will recommend you to install @nrwl/cli globally, so you can invoke nx directly without going through yarn or npm.

Adding Nx to an Existing Angular CLI workspace

If you are an Angular user, you can also add Nx to your existing Angular CLI project by running:

ng add @nrwl/workspace

Creating First Application

By default, an Nx workspace starts blank. There are no applications to build, serve, and test. To create one, you need to add capabilities to the workspace.

To add an Angular app, run:

yarn add @nrwl/angular
nx g @nrwl/angular:app myapp # or just "nx g myapp"

npm install --save-dev @nrwl/angular
nx g @nrwl/angular:app myapp # or just "nx g myapp"

To add a React app, run:

yarn add @nrwl/react
nx g @nrwl/react:app myapp # or just "nx g myapp"

npm install --save-dev @nrwl/react
nx g @nrwl/react:app myapp # or just "nx g myapp"

To add a web components app, run:

yarn add @nrwl/web
nx g @nrwl/web:app myapp # or just "nx g myapp"

npm install --save-dev @nrwl/web
nx g @nrwl/web:app myapp # or just "nx g myapp"

If nx g fails, use: yarn nx g @nrwl/web:app myapp or npm run nx -- g @nrwl/web:app myapp.

Regardless of what framework you chose, the resulting file tree will look like this:

<workspace name>/
├── apps/
│   ├── myapp/
│   └── myapp-e2e/
├── libs/
├── tools/
├── nx.json
├── package.json
├── tsconfig.json
└── tslint.json

Serving Application

• Run nx serve myapp to serve the newly generated application!
• Run nx test myapp to test it.
• Run nx e2e myapp-e2e to run e2e tests for it.

Angular users can also run ng g/serve/test/e2e.

You are good to go!

Quick Start & Documentation

Documentation

• Nx Documentation and Guides
• Nx blog posts

Books

• Enterprise Monorepo Patterns

Videos

• Nx Quickstart - How to Scale a JavaScript Project
• Video course on using Nx Workspaces

Talks

• Angular at Large Organizations
• Nx: The New Way to Build Enterprise Angular Apps
• Supercharging the Angular CLI
• Hands on Full Stack development with Nx and Bazel

Misc

• nx-examples repo has branches for different nx comments to display expected behavior and example app and libraries. Check out the branch (workspace, ngrx...) to see what gets created for you. More info on readme.
• xplat - Cross-platform tools for Nx workspaces

Want to help?

If you want to file a bug or submit a PR, read up on our guidelines for contributing.

Core Team

Victor Savkin	Jason Jean	Benjamin Cabanes
vsavkin	FrozenPandaz	bcabanes