How to delete object from array in firestore

Question

I have a problem with deleting an Object out of an Array in firestore. I have this data in firestore:

And now I would like to delete e.g the second Object out of the posts Array.

Code:

 deletePic () {
  let docId = `${this.currentUser.uid}`

   fb.usersCollection.doc(docId).update({
     posts: firebase.firestore.FieldValue.arrayRemove()
   })
  .catch(function(error) {
      console.error("Error removing document: ", error);
  });
}

But I do not know how to define arrayRemove()

These are the pictures and each one has a delete button to delete the picture.

See stackoverflow.com/questions/52150545/…

rolznz
– rolznz

2019-11-12 03:48:38 +00:00
Commented Nov 12, 2019 at 3:48 — rolznz
– rolznz, Commented Nov 12, 2019 at 3:48

Community · Accepted Answer · 2020-06-20 09:12:55Z

58

You could also use the arrayRemove method from the FieldValue helper.

docRef.update({
   array: FieldValue.arrayRemove('idToRemove');
});

https://firebase.googleblog.com/2018/08/better-arrays-in-cloud-firestore.html

edited Jun 20, 2020 at 9:12

CommunityBot

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answered Jan 15, 2020 at 4:20

Evin1_

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2 Comments

Patrik Spišák Over a year ago

This one work only for simple arrays as ["test","test2"] not if u have array of objects [{},{},{}]

Walter Monecke Over a year ago

@PatrikSpišák instead of saving an array convert is to a map before.

Fabien Greard · Accepted Answer · 2021-03-24 01:13:55Z

21

EDIT: Warning Do not use my solution as it is more than 3 years old, nowadays there is new solution : https://stackoverflow.com/a/59745086/6668441 Mine was a pure js one and is a bad pattern.

Can't you use filter ? And then return the new posts array to your fb.usersCollection method

//deleteId is the id from the post you want to delete
posts.filter(post => post.id !== deleteId);

edit : So This should be something like :

 deletePic (deleteId) {
  let docId = `${this.currentUser.uid}`

   //deleteId is the id from the post you want to delete

   fb.usersCollection.doc(docId).update({
     posts: posts.filter(post => post.id !== deleteId);
   })
  .catch(function(error) {
      console.error("Error removing document: ", error);
  });
}

edited Mar 24, 2021 at 1:13

answered Sep 3, 2018 at 13:13

Fabien Greard

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8 Comments

Lukas Over a year ago

and where to set the delete() or arrayRemove()?

Fabien Greard Over a year ago

This will store a new array without the post you delete, so this is your delete() method

Fabien Greard Over a year ago

I updated my answer, then you must get the deleteId from the user click delete button

Lukas Over a year ago

the deleteId should contain inside the object or?

BorisD Over a year ago

If you are working with a big amount of data, you w'll download all the elements to your app just to delete one. It's not optimized.

|

Ido Bar Lev · Accepted Answer · 2020-11-09 13:34:43Z

14

You can preform delete of an object in the array by using arrayRemove function. But, you'll need to provide an object. That object needs to be identical to the one in your doc array on the firestore collection.

For example:

The following code will delete obj from myArray array, but only if obj exactly exist in that array.

const obj = { field1, field2 ... } 

collectionRef.doc(docId).update({
    myArray: firebase.firestore.FieldValue.arrayRemove(obj)
})

answered Nov 9, 2020 at 13:34

Ido Bar Lev

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Comments

Volkov Maxim · Accepted Answer · 2020-11-08 17:25:35Z

3

Update elements in an array

If your document contains an array field, you can use arrayUnion() and arrayRemove() to add and remove elements. arrayUnion() adds elements to an array but only elements not already present. arrayRemove() removes all instances of each given element.

// Atomically remove a region from the 'regions' array field.
city_ref.update({u'regions': firestore.ArrayRemove([u'east_coast'])})

answered Nov 8, 2020 at 17:25

Volkov Maxim

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Comments

jogarcia · Accepted Answer · 2024-06-05 11:23:24Z

0

If you're using Firebase V9 (modular), you can simply import arrayRemove from Firestore like so:

import { doc, updateDoc, arrayRemove } from 'firebase/firestore';

const docRef = doc(db, 'collection', 'doc');
await updateDoc(docRef, {
  arrayName: arrayRemove('elementName')
});

edited Jun 5, 2024 at 11:23

jogarcia

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answered Oct 1, 2021 at 20:16

Delphin RUKUNDO

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