Problem with retrieving data from firebase database

Question

I have a problem retrieveing data from firebase database. The data structure is like this:

posts:{ 
    (Random key):{
       post:{
           text: "random text"
           title: "title of some kind"
           username: "username"
       }
  }
}

and the code I tried to retrieve text is:

database.ref("posts").orderByChild("post").on('value', function(snapshot){
       console.log(snapshot.val().text);
   })

I am new to this firebase thing, so i am sorry if it's a stupid question.

post is not a direct child of posts, so you cannot orderByChild() of that nested property. — Alexander Staroselsky
– Alexander Staroselsky, Commented Sep 15, 2019 at 1:34

Constantin Beer · Accepted Answer · 2019-09-15 01:54:20Z

1

You have to change your code like this:

database.ref("posts").child(randomKey).on('value', function(snapshot){
       console.log(snapshot.child("post").child("text").val());
   })

Your snapshot is a DataSnapshot and it contains a child() method that is a DataSnapshot itself. To get your text field you just have to use chield("text") and get then the val().

edited Sep 15, 2019 at 1:54

answered Sep 15, 2019 at 1:40

Constantin Beer

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4 Comments

The Selected One Over a year ago

It gives me value of null

Constantin Beer Over a year ago

oh saw your Random key part. I will edit my answer

The Selected One Over a year ago

how do i define that randomKey part? I have no idea how to get that, these are automatically created by firebase on saving data

Constantin Beer Over a year ago

Are you trying to get every value of your text field or just a single one?

Mukul Kumar Jha · Accepted Answer · 2019-09-15 02:01:19Z

1

First you can sort the result by using orderBy on any attributes on post. For example


var sortedpost = firebase.database().ref('posts').orderByChild('post/text');

Or simply you can also use orderByKey to sort based on the document ID.

After this you can get the result you are looking for using on listener as below.

    sortedpost.on('value', function(snapshot){
       console.log(snapshot.val());
   })

edited Sep 15, 2019 at 2:01

answered Sep 15, 2019 at 1:40

Mukul Kumar Jha

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3 Comments

The Selected One Over a year ago

But how can i bypass that random key part? because post is random keys child.

Mukul Kumar Jha Over a year ago

It will look into the nested child by itself. And why don't you add some meaningfull docID which can be done at the time of adding any data in firebase

Mukul Kumar Jha Over a year ago

docID is different for every post ( which should be :p) so you cannot just create a hard coded path for it, and if you want to sort the data based on the docID itself then you can use orderBykey()

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