@lightspeed/config-jest


Introduction

Jest dependencies and configuration for both JavaScript and TypeScript in a convenient package.

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This configuration is meant for Babel+TypeScript projects only, which is our default setup for Lightspeed web applications. For pure TypeScript projects, please use ts-jest directly instead.

Quick Start

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Install the dependencies (@types/jest is only needed if your project uses TypeScript):

``sh
yarn add -D @lightspeed/config-jest jest @types/jest
`

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Consume the Jest configuration by creating a jest.config.js file:

`js
// jest.config.js
module.exports = require('@lightspeed/config-jest');
`

Optionally, extend the configuration as you see fit:

`js
// jest.config.js
const baseConfig = require('@lightspeed/config-jest');

module.exports = Object.assign(baseConfig, {
testPathIgnorePatterns: ['/some-dir'],
});
`

You can also add your own jest.setup.js file with setupFilesAfterEnv:

`js
// jest.config.js
const baseConfig = require('@lightspeed/config-jest');

module.exports = Object.assign(baseConfig, {
setupFilesAfterEnv: ['/jest.setup.js'],
});
`

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If in a React project, we highly recommend installing @testing-library/react and @testing-library/jest-dom as they are amazing testing tools on top of Jest for React.

Install dependencies:

`sh
yarn add -D @testing-library/react @testing-library/jest-dom
`

Then, in your jest.setup.js file, add:

`js
// add some helpful assertions
require('@testing-library/jest-dom/extend-expect');
`

Note that react-testing-library methods will be available out of the box after installing the library

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For node-only projects, you must set testEnvironment to node instead of the default jsdom:

`js
// jest.config.js
const baseConfig = require('@lightspeed/config-jest');

module.exports = Object.assign(baseConfig, {
testEnvironment: 'node',
});
`

Add an npm script to run your tests

Finally, add an npm script to run jest:

`json
{
"scripts": {
"test": "jest"
}
}
`

By default jest will run tests on any file named with *.test.(js|jsx|ts|tsx)`.

Go forth and test away! 🎉