Firebase NodeJs ReferenceError: Promise is not defined

Question

I came across this error message when trying to deploy a firebase node application to a virtual private server:

/home/.../Backend/node_modules/firebase-admin/lib/firebase-namespace.js:195
        this.Promise = Promise;
                       ^
ReferenceError: Promise is not defined
    at new FirebaseNamespace (/home/.../Backend/node_modules/firebase-admin/lib/firebase-namespace.js:195:24)
    at Object.<anonymous> (/home/.../Backend/node_modules/firebase-admin/lib/default-namespace.js:5:21)
    at Module._compile (module.js:456:26)
    at Object.Module._extensions..js (module.js:474:10)
    at Module.load (module.js:356:32)
    at Function.Module._load (module.js:312:12)
    at Module.require (module.js:364:17)
    at require (module.js:380:17)
    at Object.<anonymous> (/home/.../Backend/node_modules/firebase-admin/lib/index.js:4:16)
    at Module._compile (module.js:456:26)

On my local environment, this node application runs without any problem. Both environments are having the same node, npm, and "firebase-admin" module version.

So, I followed the suggestion from here and modified the "firebase-admin" module files on the virtual server. By adding

var Promise = require('es6-promise').Promise;

to some of the module source files manually, I can get rid of the error messages. After that, nothing can be read from the firebase database.

My code section

firebaseDatabase.ref("...").once('value').then(function(snapshot){
  ....
});

which reads the contents of firebase with no problem on my local environment, never have its "then" called on the virtual server.

What am I doing wrong? Any suggestion is appreciated.

npm version: 3.10.0 ; node version: 7.1.0; v8 version: 5.4.500.36; firebase-admin version: 4.0.3; — Peter Peng, Dec 04 '16 at 22:02

Peter Peng · Accepted Answer · 2016-12-05T19:50:48.473

I manage to solved the problem. Just in case if anyone run into the same issue, here are the steps how I fixed it:

For my case, I removed all the modifications I made to the firebase-admin module.
install "es6-promise" if you haven't. (npm install es6-promise --save)
Add the following line to your "server.js" file:

require('es6-promise').polyfill();

Notice that we don't assign the result of polyfill() to any variable. The polyfill() method will patch the global environment (in this case to the Promise name) when called.

score 0 · Answer 2 · answered Mar 14 '17 at 13:40

I encountered this issue as soon as I firebase init. I did not change or added any codes in the generated scripts. I did solve the issue and was able to deploy by:

Going to the functions folder "cd functions"
sudo npm install es6-promise --save
Browse to the functions/node_modules/firebase-admin/lib/firebase-namespace.js
Add this on top

var Promise = require('es6-promise').Promise;

Your header should look like this:

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
var deep_copy_1 = require("./utils/deep-copy");
var error_1 = require("./utils/error");
var firebase_app_1 = require("./firebase-app");
var credential_1 = require("./auth/credential");
var DEFAULT_APP_NAME = '[DEFAULT]';
var globalAppDefaultCred;
var globalCertCreds = {};
var globalRefreshTokenCreds = {};
var Promise = require('es6-promise').Promise;

Firebase NodeJs ReferenceError: Promise is not defined

2 Answers2