ref() or Child() when reading firebase web data

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What’s the difference between ref() and child() firebase? When should I use one or the other? Is there any difference in performance?

javascript firebase realtime-database

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The 2 are methods of different classes, but return the same thing: a Reference. The ref() is of class Database and the child() class Reference.

Let’s see how these methods work:

  1. ref() - returns a reference to the database node passed as parameter. If it has no specified parameter, it returns the reference to the root node of the database.
  2. child() - also returns a reference to a database node. But the difference is that it serves to access the sub-nodes within a Reference.

Bearing in mind that the child() is from the Reference class and also returns a Reference object, you can use chained Childs as follows:

ref.child("users").child("uid1").child("nome")

But the same does not happen with the ref(). Is not possible do ref.ref("users").ref("uid1").ref("nome").

It is also possible to access the sub-nodes using the ref():

ref = database.ref("users/uid1/nome");

And using the child():

ref = database.ref().child("users/uid1/nome");
//ou até
ref = database.ref("users").child("uid1/nome")

In short: In the end, the 2 methods return the same thing and have no difference in terms of performance. Use the method that makes you more comfortable.

  • There’s a difference in performance chlid('a/b') and child('a').child('b')?

  • There is nothing documented by Firebase. But if you have any difference will be minimal and negligible.

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