CODEWITHSUNDEEP
javascriptnode.jsfirebasefirebase-realtime-databasegoogle-cloud-functions
Sergio
Sergio

Reputation: 1912

How to delete a node with a Cloud Function?

This is my Firebase Database structure:

project
|
|- Users
   |
   | - 00001
       |
       | - Likes
       |   |
       |   | - 00001
       |       |
       |       | - 'whatever':'whatever'
       |
       | - Unlikes
           |
           | - 00002
               |
               | - 'whatever':'whatever'

What I want is a DB triggered function that when the user adds to Likes the item with id 00002, removes it automatically from Unlikes.

I am using JavaScript and this is the function I've got right now:

exports.likeItem = functions.database.ref('/Users/{userId}/Likes/{itemId}'.toString()).onCreate((like, context) => {
    return like.ref.parent.child('/Unlikes').once('value', (unlikes) => {
        unlikes.ref.child(context.params.itemId).set(null);
    });
});

The function is triggered correctly when the like is written, but doesn't remove the unlike.

The error is this:

'parent' of undefined at exports.likeItem.functions.database.ref.onCreate

Upvotes: 1

Views: 108

Answers (1)

Renaud Tarnec
Renaud Tarnec

Reputation: 83093

If I understood correctly what you try to achieve, the following should do the trick.

exports.likeItem = functions.database
  .ref('/Users/{userId}/Likes/{itemId}')
  .onCreate((like, context) => {
    return like.ref.parent.parent
      .child('/Unlikes/' + context.params.itemId)
      .set(null);
  });

Note that you don't need to read anything with the once() method. Just define the correct reference to delete (with like.ref.parent.parent.child(....)) and set it to null.

Upvotes: 1

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