kill my previous file on local host

I have trouble on my localhost:3000. I connected my file "smap" to localhost:3000 couple month ago when I was learning the npm. right now, I cannot remove it from local host:3000

it keep showing me the old file

smap@1.0.0 start /Users/Han cross-env NODE_ENV=development ./node_modules/.bin/hjs-dev-server Listening at http://localhost:3000 webpack built 2f3c2c9a3eec810b8e79 in 2453ms

Does anyone know how can I remove it from my local host? I tried Find: lsof -i :3000 Kill: kill -9 but it did not work.

Since I get a new file, want to connect it with localhost.

any help would be appreciated

via Mtndew