When I run "npm start" to run a React app , it doesn't give any errors but hangs forever instead

I have already run "npm install" before this and all the necessary dependencies have been installed.

I've also tried uninstalling the old version of NodeJS and installing the latest version but it's still not working.

A browser window with the React app should pop up.

My package.json file looks like this:

{
  "name": "test",
  "version": "0.1.0",
  "private": true,
  "dependencies": {
    "add": "^2.0.6",
    "bootstrap": "^4.1.3",
    "react": "^16.6.3",
    "react-bootstrap": "^0.32.4",
    "react-dom": "^16.6.3",
    "react-redux": "^5.1.1",
    "react-router-dom": "^4.3.1",
    "react-scripts": "2.1.1",
    "react-select": "^2.1.1",
    "redux": "^4.0.1",
    "yarn": "^1.12.3"
  },
  "scripts": {
    "start": "react-scripts start",
    "build": "react-scripts build",
    "test": "react-scripts test",
    "eject": "react-scripts eject"
  },
  "eslintConfig": {
    "extends": "react-app"
  },
  "browserslist": [
    ">0.2%",
    "not dead",
    "not ie <= 11",
    "not op_mini all"
  ],
  "proxy": "http://localhost:57111/"
}

Solution

There may be various reasons for the url to not automatically open up in a browser but we will know whether the server started or not by manually opening the url in the browser.

Usually the server is started in port 3000 in localhost. So the URL to access your site will be http://localhost:3000 by default when you use create-react-app.

Try opening the site manually at http://localhost:3000