Something is already running on port 6969

choosePort.md

Problem

Have you ever encountered something like Error: listen EADDRINUSE: address already in use :::3000 when your app is starting?

After which you have to change the port or shutdown whatever is running on the already used one...

Solution

npm i react-dev-utils

import { choosePort } from 'react-dev-utils/WebpackDevServerUtils'

Wherever you need to use the port, just use const port = await choosePort(HOST, PORT) instead.

If you're sure you'll be running on localhost, you can set HOST to whatever, like undefined. React uses 0.0.0.0 afaik.

+const port = await choosePort('0.0.0.0', PORT)
+http.listen(port, function () {
-http.listen(PORT, function () {
  console.log(`App started!`)
});

Result

On your app start, if the port is taken, the terminal will simply ask you to approve port changing. Press Enter and you're done.