sample.js

const calls = require('./calls');

srf.invite(async(req, res) => {
  const ms = req.app.locals.ms;
  const to_number = calls.convertToE164(req.calledNumber);
  let ep, dlg;
  try {
    const {endpoint, dialog} = await ms.connectCaller(req, res);
    ep = endpoint;
    dlg = dialog;
    const number = await calls.check_is_valid(to_number);
    if (!number) {
      console.log(`[${req.callid}] ${to_number} does not match`)
      await calls.playback_failure(endpoint);
      dialog.destroy();
      endpoint.destroy();
    }
    else {
      setHandlers(req, res, dialog, endpoint);
    }
  } catch (err) {
    console.error(err, 'Error connecting call to media server');
    res.send(503);
    if (dlg) dlg.destroy();
    if (ep) ep.destroy();
  }
});

function setHandlers(req, res, dialog, endpoint) {
  dialog.on('destroy', () => {
    console.log(`Received BYE, deleting ${req.callid}`)
    endpoint.destroy();
    //  calls.delete_call(req.call_id);
  });

}