1|server | { Error: listen EADDRINUSE: address already in use :::4040 code example

Example 1: Error: listen EADDRINUSE: address already in use :::3000

sudo lsof -i :3000

Example 2: Error: listen EADDRINUSE: address already in use :::3000

//To find the process id (PID) associated with the port
lsof -i tcp:3000 
COMMAND PID   USER  FD  TYPE DEVICE             SIZE/OFF NODE NAME 
node    44475 chen5 31u IPv4 0x8b1721168764e4bf 0t0 TCP *:strexec-s (LISTEN)
//Then to kill the process
kill -9 44475