@angular-builders/jest v18.0.0

Jest builder for Angular build facade

Allows running ng test with Jest instead of Karma & Jasmine.

Prerequisits

• Angular CLI 6
• Jest

Installation

1. Remove Karma related libraries and files:

     npm remove karma karma-chrome-launcher karma-coverage-istanbul-reporter karma-jasmine karma-jasmine-html-reporter
   		 rm karma.config.js
   		 rm src/test.ts

2. Install the builder (and jest if you still haven't): npm i -D jest @angular-builders/jest

Updating Typescript configurations

Although you run your unit tests with Jest, Protractor (e2e tests) still has to use Jasmine. Due to this fact it's possible that you favorite IDE will get confused with the typings and will propose you Jasmine types in unit tests or Jest types in e2e test. In order to avoid that kind of problems you have to specify the types explicitly:

1. In tsconfig.spec.json (src directory, used by Jest):

   "compilerOptions": {
   	...
   	"module": "commonjs",
   	"types": ["jest"]
   } 

   Make sure the module is commonjs, otherwise tests will fail at imports.

2. In tsconfig.json (root directory, used by IDE):

   "compilerOptions": {
   	...
   	"types": ["jest"]
   } 

Running with Angular CLI

• In your angular.json:

  "projects": {
      ...
      "[your-project]": {
           ...
           "architect": {
                  ...
                  "test": {
                            "builder": "@angular-builders/jest:run"
                            "options": {
                                  ... //see below
                            }

• Run the tests: ng test

Builder options

• watch - whether to run jest in watch mode, defaults to false
• coverage - whether to run jest with coverage, defaults to false
• configPath - path to jest config file, defaults to jest.config.js.
  If jest entry exists in package.json, configPath will be ignored.
  If no configuration provided (neither in package.json nor here) the default configuration is taken from the builder.

• [booleanOption] - any boolean option from Jest CLI options. For example, to run unit tests without caching use:

  "options": {
  			"no-cache": true
  }   

Migrating existing tests to Jest

Use this for automatic migration of your Jasmine tests to Jest framework.