Query a table from Firebase via NodeJS

Question

I have a table users in Firebase with these data

{
  "users" :
  [
   {"id": 1,
     "fcmToken" : "APA91bHJAzXe384OEYvfk4bKsyS1NQvteph7DwG7JRIMm_HuXg8EeNllVrsSi0v9W_Gh95ezbOStp3ZWuWl0AzFKxMaCOjN81yiz7A5qhkONrd7lP2CTkUbFErw28r3ONTLvo8c8sO7hdiWY78iar8s:APA91bHJAzXe384OEYvfk4bKsyS1NQvteph7DwG7JRIMm_HuXg8EeNllVrsSi0v9W_Gh95ezbOStp3ZWuWl0AzFKxMaCOjN81yiz7A5qhkONrd7lP2CTkUbFErw28r3ONTLvo8c8sO7h",
     "fName" : "John",
     "lName" : "Doe",
     "phone" : "9786770861"
   },
   {"id": 2,
     "fcmToken" : "APA91bHJAzXe384OEYvfk4bKsyS1NQvteph7DwG7JRIMm_HuXg8EeNllVrsSi0v9W_Gh95ezbOStp3ZWuWl0AzFKxMaCOjN81yiz7A5qhkONrd7lP2CTkUbFErw28r3ONTLvo8c8sO7hdiWY78iar8s:APA91bHJAzXe384OEYvfk4bKsyS1NQvteph7DwG7JRIMm_HuXg8EeNllVrsSi0v9W_Gh95ezbOStp3ZWuWl0AzFKxMaCOjN81yiz7A5qhkONrd7lP2CTkUbFErw28r3ONTLvo8c8sO7h",
     "fName" : "Jane",
     "lName" : "Doe",
     "phone" : "6178779690"
   }

 ]
}

after import I get this

I followed this exact post from Firebase

https://firebase.google.com/docs/reference/node/firebase.database.DataSnapshot

var admin = require("firebase-admin");

var serviceAccount = require('/Users/john/Desktop/Apps/APNS/node/mhn-app-firebase-adminsdk-bs45c-5ac3770488.json');

var firebase = admin.initializeApp({
  credential: admin.credential.cert(serviceAccount),
  databaseURL: "https://mhn-app.firebaseio.com"
});


var ref = firebase.database().ref("users");
ref.once("value")
.then(function(snapshot) {

    var users =  snapshot.child("users").val();
    console.log(users);

});

I kept getting null

⚡️  node  node app.js                                                           
>>> Done                                                                       
null                                                                           



^C                                                                             
⚡️  node

Renaud Tarnec · Accepted Answer · 2018-11-29 17:31:41Z

2

You're querying to get the /users node, and then ask for the users child in there. There is no /users/users, so you get an empty result.

The solution is:

ref.once("value").then(function(snapshot) {
    var users = snapshot.val();
    console.log(users);
});

You'll note that in the example you followed, they're also not doing snapshot.child('users/ada') in the callback.

edited Nov 29, 2018 at 17:31

Renaud Tarnec

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answered Nov 29, 2018 at 17:23

Frank van Puffelen

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