send message to slack using firebase cloud function

index.js

const functions = require('firebase-functions');
const request = require('request');

exports.addMessageToSlack = functions.https.onRequest((req, resp) => {
  return new Promise((resolve, reject) => {
  const message = array['message'];
    request.post(
      "https://hooks.slack.com/X/Y/Z",
      { json: { text: `You have a new message: ${message}`} }
    )
    .on('response', function(response) {
      if(response.statusCode === 200) {
        resp.send(JSON.stringify('success'));
        resolve();
      } else {
        reject(response);
      }
      })
  });
});