React Setting up Vite with Jest

Introduction

This is a page to help set up vite with jest which did not work out of the box

Steps

Setup Project

Create project

npm init vite@latest demo-project -- --template react-ts

Add Node Engine

{
  "name": "demo-project",
  "version": "0.0.0",
  "engines":{
    "node": ">=16.13.0",
    "npm": ">=8.1.0"
  },
  // ...
}

Install and test Jest

Install Jest

npm install jest --save-dev

Add to packages Test

  "scripts":{
    // ...
    "test": "jest"
  },

Add a dummy test in __test__/demo.test.js. Note the js

test('demo', () => {
  expect(true).toBe(true)
})

Running the test should work

npm run test

Setup Typescript

Next lets use typescript

npm install ts-jest @types/jest --save-dev

And tell jest to use typescript in jest.config.cjs

module.exports = {
  preset: 'ts-jest',
}

Note the cjs and not js. This is quite important and will produce the error

ReferenceError: module is not defined in ES module scope
This file is being treated as an ES module because it has a '.js' file extension and '/home/iwiseman/dev/projects/vite_bunler/demo-project/package.json' contains "type": "module". To treat it as a CommonJS script, rename it to use the '.cjs' file extension.
    at file:///home/iwiseman/dev/projects/vite_bunler/demo-project/jest.config.js:1:1
    at ModuleJob.run (node:internal/modules/esm/module_job:194:25)

Add other Testing libraries

Now lets add react testing library

npm install @testing-library/react @testing-library/jest-dom --save-dev

Create jest-environment-jsdom.cjs

module.exports = {
    preset: 'ts-jest',
    testEnvironment: 'jest-environment-jsdom', // this line was added
}

And a Test case

import '@testing-library/jest-dom'
import { render, screen } from '@testing-library/react'
import App from '../App'

it('renders hello message', () => {
  render(<App />)
  expect(screen.getByText('Hello Vite + React!')).toBeInTheDocument()
})