express and react Error: listen EADDRINUSE: address already in use :::4000 code example

Example 1: EADDRINUSE: address already in use :::5000

sudo lsof -i :3000

Example 2: EADDRINUSE: address already in use

sudo lsof -i :<PORT>
kill -9 <PID>

Example 3: Error: listen EADDRINUSE: address already in use :::31641

ps aux | grep node //gets all the nodes and list of PID
kill -9 {PID}