Angular schematic for adding Jest and the required files to an Angular CLI project
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Jest Angular Schematic

npm (scoped)

Add Jest to an Angular CLI project

This schematic will:

  • install Jest, it's dependencies, and new scripts
  • add necessary files for Jest to work with Angular
  • remove unnecessary Karma files and configuration

Usage 🚀

Install globally

npm install -g @briebug/jest-schematic

Then in an Angular CLI project run

ng g @briebug/jest-schematic:add


Optionally run as one command in an Angular CLI app directory. Note this will add the schematic as a dependency to your project.

ng add @briebug/jest-schematic


If you're experiencing issues when trying to run your tests with Jest, please view the troubleshooting section for jest-preset-angular which this schematic utilizes.

A common issues revolves around library dependencies. For example if your app depends on NgRx you'll need to tell Jest to compile the sources explicitly by appending it to the transformIgnorePatterns property in the jest.config.js file.

module.exports = {
  transformIgnorePatterns: ['node_modules/(?!(jest-test|@ngrx))'],

Issues with this schematic can be filed here.

Development 🛠

Getting started

yarn && yarn link:sandbox

Test schematic changes against this repositories Angular CLI sandbox

When running locally, schematic changes will be applied to the test app in the ./sandbox directory. The sandbox is a bare CLI app allows for testing schematics changes.

Run the following when a schematic change is made:

yarn build:clean:launch

build:clean:launch will compile the Typescript, reset the sandbox to is current version controlled state removing un-tracked files, and run the schematic against the sandbox. This will be your main development command.

Be careful not to check in changes to the sandbox directory unless necessary.

Test schematics against a local project

  • run yarn build to compile the schematic in watch mode
  • open another shell, cd into the local repo you want to run the schematic against, and run yarn link @briebug/jest-schematic. This assumes you've run yarn link in this repo on your machine.
    • this will symlink the projects so that the Jest schematic command runs from you're local filesystem
  • in the local repo you want to run the schematic against, run ng g @briebug/jest-schematic:add

Dev tips

For faster developing, find and comment out the following line to avoid npm installing dependencies

context.addTask(new NodePackageInstallTask());

Reset sandbox to its version controlled state

This will reset the sandbox folder to its HEAD commit and remove un-tracked files.

yarn clean

Compile the schematics

Compile the typescript files in watch mode

yarn build:watch

Compile the typescript files once

yarn build


Test local sandbox for regressions

Run a series of standard tests to ensure the ./sandbox continues to function normally

yarn test

Getting Started With Schematics

This repository is a basic Schematic implementation that serves as a starting point to create and publish Schematics to NPM.

Schematic Testing

To test locally, install @angular-devkit/schematics globally and use the schematics command line tool. That tool acts the same as the generate command of the Angular CLI, but also has a debug mode.

Check the documentation with

schematics --help

Unit Testing

yarn test:unit will run the unit tests, using Jasmine as a runner and test framework.


Publishing is handled by np. Ensure you have push access to this repo and are a @briebug NPM contributor. Several options are available for releases such as npm run release --no-publish.

Once all features are merged into master:

  1. on your machine, checkout master
  2. pull latest
  3. npm run release
  4. select the next appropriate version given the changes being added
  5. copy the Commits: displayed in your shell
  6. release-commits
  7. edit the new release tag, and paste in the change notes and supply a title if appropriate
  8. edit-github-release