I know from this question and answer on Super User Site running on localhost on desktop is unreachable on android device (PS: this question continues on the question in the link) that the command
try ng serve
--host option as explained in this issue: https://github.com/angular/angular-cli/issues/1793 comment by intellix.
ng serve --host 0.0.0.0
<local ip adress>:4200from any device on the same network.
otherwise try https://ngrok.com/ to open a tunnel from your local network to your computers localhost. Basically your computer forwards the 4200 port to an external ip and port that any device on the network can access.