npm add --dev jest babel-jest @babel/preset-env @babel/preset-react npm add --dev @testing-library/react @types/jest jest-environment-jsdom
"scripts: { ... "test": "jest --watchAll"
module.exports = { presets: [ [ '@babel/preset-env', { targets: { esmodules: true } } ], [ '@babel/preset-react', { runtime: 'automatic' } ], ], };
module.exports = { testEnvironment: 'jest-environment-jsdom', setupFiles: ['./jest.setup.js'] }
npm i -D @testing-library/react
import 'whatwg-fetch'; // <-- npm add whatwg-fetch