How to Create a React App with a Node Backend

mkdir react-node-app
cd react-node-app
npm init -y
npm i nodemon --save-dev
npm i concurrently --save-dev
npm i express
touch server.js

package.json

...
"scripts": {
    "start": "if-env NODE_ENV=production && npm run start:prod || npm run start:dev",
    "start:dev": "concurrently \"nodemon --ignore 'client/*'\" \"npm run client\"",
    "client": "cd client && npm run start"
},
...

npx create-react-app client

client/package.json

...
"proxy": "http://localhost:3001",
...

cd client
add fetch("/api') to src/App.js
npm start