Node.js request sending downstream POST with Google Firebase Cloud Message

NodeDownstreamFirebaseCloudMessage.js

/* 
 Example of Node.JS to send downstream cloud message with Firebase
 NPM package request is needed in this code gist
*/

// Firebase auth key
var serverKey = "Firebase Server Key";
var clientToken= "Client Device Token"

// Payload message data
var deviceId = req.query.deviceId;
var eventName = req.query.eventName;
var value = req.query.value;

var options = {
  url: 'https://fcm.googleapis.com/fcm/send',
  headers: {
    'Authorization': 'key=' + serverKey
  },
  json: {
  	"to": clientToken,
	"data": {
		deviceId: deviceId,
		eventName: eventName,
		value: value
	}
  }
};

request.post(options, function optionalCallback(err, httpResponse, body) {
	
  if (err) {
    return console.error('ERROR - FIREBASE POST failed:', err);
  }
  
  // Success
	
});