Get document data from Firebase Firestore in Node JS

Question

after not finding anything online, I decided to write here. I need to get all the document in the /user/uid collection in Node JS. When I use the Firebase code it replies like this:

Promise {<pending>}

Please help me!

PS: I don't want to use Firebase Admin SDK and await.

"Full" code

var express = require('express');

const { initializeApp } = require("firebase/app");
const { getDatabase, ref, get, child, set, onValue} = require("firebase/database");
const { getFirestore, collection, getDoc, doc} = require("firebase/firestore");

const firebaseApp = initializeApp(firebaseConfig);

// Get a reference to the database service

var app = express();

const PORT = process.env.PORT || 5050

app.get('/', (req, res) => {
    res.send('This is my demo project')
});

const db = getDatabase();
const firestore = getFirestore();


const document = getDoc(doc(collection(firestore, 'users'), "BW5kylV6rtZXtYibpKGc2m1asRm1"));
  
console.log(document);

//Response: "Promise {<pending>}""

Renaud Tarnec · Accepted Answer · 2022-02-10 20:18:37Z

1

Firebase method calls are asynchronous. So for both the Admin SDK or the JS SDK you have to deal with the asynchronicity, either by using then or by using async/await.

If you receive Promise {<pending>} it is because the asynchronous method getDoc returns a Promise and this promise is not fulfilled, but is still pending.

So you need to dive into the documentation on how to use Promises... or the async/await keywords.

In your case, the following will do the trick:

getDoc(doc(collection(firestore, 'users'), "BW5kylV6rtZXtYibpKGc2m1asRm1"))
.then(snap => {
   console.log(snap.data())
})

However, if you write this code for running on a Node server you own, I would recommend to use the Admin SDK.

edited Feb 10, 2022 at 20:18

answered Feb 10, 2022 at 20:07

Renaud Tarnec

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4 Comments

Matteo Over a year ago

Thanks for the prompt reply! The code you gave me works. I wanted to ask you one last thing, why do you advise me to use the Admin SDK, keeping the credentials is no less secure? I have to perform mostly read-only operations on Firestore and Realtime DB. Thanks so much

Renaud Tarnec Over a year ago

Glad that I could help you. To answer your question I have myself a question: You mention that you use Node.js. Where does your code run? On a server you own?

Matteo Over a year ago

I need to build APIs that take the values from the database. For now I hosto it locally.

Renaud Tarnec Over a year ago

Ok, so you could also use one or more Cloud Functions. In any case, whether you use your own server or a Cloud Fucntion, the recommended SDK in this case is the Admin SDK. See here for more details.

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