Answers for "insert javascript file in html"

mac terminal find process by port

sudo lsof -i tcp:3000

kill all ports mac

lsof -n -i TCP:8080
COMMAND   PID   USER   FD   TYPE             DEVICE SIZE/OFF NODE NAME
node     54762   user   23u  IPv4 XXXXXXXXX      0t0  TCP 127.0.0.1:http-alt (LISTEN)
PID // is second field in the response . Then, kill that process:

kill -9 54762 // here put PID number found on the table 54762

killing a port mac

sudo lsof -i :3000

killing a port mac

kill -9 <PID>

kill process on port 3000 mac

kill $(lsof -ti:3000,3001,8080)

import js in html

<script type="text/javascript" src="yourfile.js"></script>