to add typescript to react app code example
Example 1: create react app typescript
npx create-react-app app-name --template typescript
# or using yarn
yarn create react-app app-name --template typescript
Example 2: add typescript in create react app
npm install --save typescript @types/node @types/react @types/react-dom @types/jest
# or
yarn add typescript @types/node @types/react @types/react-dom @types/jest