how to use jest javascript code example

Example 1: how to install jest

npm install --save-dev jest

// Yarn
yarn add --dev jest

Example 2: what is jest

Jest is a JavaScript testing framework maintained by Facebook, Inc. with a
focus on simplicity.

It works with projects using: Babel, TypeScript, Node.js, React, Angular and
Vue.js.

It aims to work out of the box and config free.