I have checked both commands npm start and npm run start, both works perfectly. I used create-react-app. But to make configuration changes in the C
npm start is just an alias for npm run start. Look in the package.json under the "scripts" property, to see the commands available. For example, for create-react-app:
"scripts": {
"start": "react-scripts start",
"build": "react-scripts build",
"test": "react-scripts test",
"eject": "react-scripts eject"
}