jest-example

• Jest Example with react via typescript

Install

Install React

yarn add react react-dom
yarn add -D @types/react @types/react-dom babel-preset-env babel-preset-react babel-preset-typescript parcel-bundler ts-node typescript

Install ts-jest

yarn add -D ts-jest react-test-renderer @types/jest @types/react-test-renderer

Install enzyme

• A library that's useful for testing the react components
• Enzyme github

yarn add -D enzyme enzyme-adapter-react-16 @types/enzyme @types/enzyme-adapter-react-16

Jest Snapshot Concept

• Jest create the sanpshot automatically.
• After when the test fail, check the source code was updated or not.
• If the source code was updated, update shanpshot.
• If the source code isn't updated, there is a bug