JAVASCRIPT

set port in react app

//in package.json

"start": "react-scripts start"
t0
//linux
"start": "PORT=3006 react-scripts start"
or 
"start": "export PORT=3006 react-scripts start"
//windows
"start": "set PORT=3006 && react-scripts start"

how to give port for react application

//If you don't want to set the environment variable, another option is to modify the scripts part of package.json from:

"start": "react-scripts start"
//to

//Linux (tested on Ubuntu 14.04/16.04) and MacOS (tested by aswin-s on MacOS Sierra 10.12.4):

"start": "PORT=3006 react-scripts start"
//or (may be) more general solution by IsaacPak

"start": "export PORT=3006 react-scripts start"
//Windows 

"start": "set PORT=3006 && react-scripts start"

react port

// Ubuntu / CentOS / RHEL / MacOS environment:

...
  "scripts": {
    "start": "PORT=8000 react-app-rewired start",
    "build": "react-app-rewired build",
    "test": "react-app-rewired test --env=jsdom",
    "eject": "react-app-rewired eject"
  }
...

how to change port in react js

PORT=5010 react-scripts start

react port

#Create a .env file at your project root and specify port number there. Like:
PORT=3005