This allows you to dynamically set ngrok urls in your node.js apps. This allows you to use the free version of ngrok without constantly updating the urls each time 'ngrok http ' is run.
ngrok http <port>
import ngrokaddress from 'ngrok-address';
import ngfrokaddress from 'ngrok-address';
ngrokaddress(8800).then(response => console.log(response));