Learn JavaScript Promises (Pt.1) with HTTP Triggers in Cloud Functions - Firecasts

In this Firecast, Doug Stevenson covers programming with JavaScript Promises in an HTTP trigger in Cloud Functions.

If you’re going to write code for Cloud Functions, you definitely need to know about how promises work. Nearly all the functions you write will use promises, and, if you don’t do it correctly, your code may fail in mysterious ways. In this tutorial, you’ll learn the basics of using promises in your HTTP functions.

[ndipatri]

Doug, your contributions to the dev community are superb and most definitely appreciated! Keep up the great work!

[RiceCodes]

Thanks so much for these videos! I'm so impressed with the documentation the Firebase team has put together, especially videos like this that go beyond explaining how Firebase works, but actually teach more basic Javascript concepts. Such a great resource!

[pierrechavaroche]

You are very talented to explain things. Very good job Doug! ☺️

[teamexit]

He often answers my questions on SO with Frank, the master. Thank you all, sincerely [:

[yogenp]

Love the videos on Cloud Functions. Keep 'em coming.

[clearwavepro]

Great video, the speaker is very friendly, speaks at a good pace and speaks clearly. First video ever on promises, so very glad you made this! Thanks!

[fotios]

Congrats Doug and the Firebase team in general! This firebase serve... thing is so good!!!

[lgopt]

Thanks.. For being more informative & more patient than the last similar video made by Jen Person. This made stuff much more clear. Way to go

[robertosoriano]

Thanks Doug!! Everything was so incredibly clear. You make these sound so easy.

[fotios]

@3:17, admin.initializeApp() but how come we don't need to add the firebaseConfig like

var firebaseConfig = {
apiKey: "AIza...",
authDomain: "name...",
databaseURL: "https://...",
projectId: "id...",
storageBucket: "Bucket...",
messagingSenderId: "1...",
appId: "...",
measurementId: "G-..."
};
// Initialize Firebase

[MattPenner]

Not sure why but when I attempt to run the function locally I get {} as the response and the following error in the firebase-debug.log: "Error: Could not load the default credentials." Yet when I deploy the function it works fine, returning the object from Firestore. Looking at the docs it seems that when running locally functions and Firestore should already have the permissions necessary. Tried creating a service key and passing that to admin.initializeApp but same result. Any ideas?

[FelipeTrovadeAraujo]

For those that are facing problems to run locally (not authenticated problem): Go the project settings in your firebase console / service accounts and click in the button "generate new primary key", save the file.
In the code initialize your function like this:

const serviceAccount =
admin.initializeApp({ credential: })

admin.json is the file that you download (pay attention to the json file path).
In the beginning, when we create the project, where we choose "functions" in the console I also have chosen firebase emulator (I think it's necessary in the most recent versions to run locally)

[navieses]

Thank you sir! Great content, easy to follow. Love Firebase ;) Cheers!

[lakshmisravyagajavalli]

Can I have the referencing videos using JavaScript rather than type script

[resonancerealty]

With the latest firebase admin - you have to set up your service account key :

import * as admin from 'firebase-admin';
var serviceAccount = require('path to your key here');
admin.initializeApp({
credential: admin.credential.cert(serviceAccount),
databaseURL: 'Your database URL',
});

[titaniumwolf]

Thank you very much! This is way easier than reading docs.

[wesleybarnes]

Quick question guys, how would you actually then test the local function -> Lets say an onRequest function needs a payload, would you add your payload to the end of the url? And is it working on your database directly at google (not local)? Really need to know how to get the local testing setup working. Thank you

[salahxx]

Thank Doug!
Shouldn't you return the promise at the end?

[fotios]

When I try on localhost I get an empty object { }. But it works fine if I deploy it...

[mayursoftwarewalaa]

wow, its very use full to us, Thank you sir