throw er; // Unhandled 'error' event ^ Error: listen EADDRINUSE: address already in use :::3000 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

Example 3: Error: listen EADDRINUSE: address already in use :::3000

C:\Windows\System32>taskkill /F /IM node.exe
SUCCESS: The process "node.exe" with PID 11008 has been terminated.

Example 4: Error: listen EADDRINUSE: address already in use :::3000

kill -9 {PID}