flutter firestore, add new object in array

Question

I have array of objects, I want to add new object when user enter new data in the array?

Firestore.instance.collection(city).document('Attractions').updateData(
                        "data", FieldValue.arrayUnion(obj)
                      );

This shows error, How can I achieve this with flutter?

Edit your Question with updated code & new Error – anmol.majhail Dec 07 '18 at 10:50 — anmol.majhail, Dec 07 '18 at 10:50

score 47 · Accepted Answer · answered Dec 07 '18 at 08:03

47

Right Format is :

Firestore.instance.collection(city).document('Attractions').updateData({"data": FieldValue.arrayUnion(obj)});

updateData Take Map<String,dynamic> as data.

In your Code you are having , as separator between key - value instead it should be :

answered Dec 07 '18 at 08:03

anmol.majhail

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Thanks for you help, I tried it, But now I am getting error: – Sami Ullah Dec 07 '18 at 10:19
1

The error states: The argument type 'Map' can't be assigned to the parameter type 'List' – Sami Ullah Dec 07 '18 at 10:20
You need to add more Code for me to debug. Plus the new error could be of some other area of code also. – anmol.majhail Dec 07 '18 at 10:43
5

FieldValue.arrayUnion takes in a list. Use this and it should fix your error - Firestore.instance.collection(city).document('Attractions').updateData({"data": FieldValue.arrayUnion([obj])}); – sharath Feb 19 '20 at 04:48

Gabe · Answer 2 · 2021-01-13T14:41:32.743

17

@anmol.majhail 's is right, but to solve @Sami Ullah's problem, you must first make a list and add the object into the list like this:

var list = [objectBeingAdded];
Firestore.instance.collection('city').document('Attractions').updateData({"data": FieldValue.arrayUnion(list)});

edited Jan 13 '21 at 14:41

answered Sep 01 '19 at 13:12

Gabe

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where are you using 'list' objects while updating your data in firestore? – Salman Khan Mar 29 '20 at 08:08
He meant to use it instead of 'obj' in FieldValue.arrayUnion(obj). Easier way is just to do FieldValue.arrayUnion([obj]). – Alex Hartford Sep 18 '20 at 17:14
1

@AlexHartford I know, I just thought that it would be easier to understand and notice if I made it two statements instead of one – Gabe Sep 18 '20 at 18:35
You still need to correct obj -> list with your current answer. – Alex Hartford Sep 18 '20 at 21:47
wrapping obj with [] did it for me. thanks. – Gel Dec 02 '20 at 08:09

score 7 · Answer 3 · answered Jun 06 '21 at 14:09

Null safe code:

Say this is the data you want to add

Map<String, dynamic> someData = {
  'foo': 1,
  'bar': true,
};

Add the data with unique auto-generated ID:

var collection = FirebaseFirestore.instance.collection('collection');
collection 
    .add(someData) 
    .then((_) => print('Added'))
    .catchError((error) => print('Add failed: $error'));

Add the data with your own ID:

var collection = FirebaseFirestore.instance.collection('collection');
collection 
    .doc('document_id') // <-- Document ID
    .set(someData) 
    .then((_) => print('Added'))
    .catchError((error) => print('Add failed: $error'));

Add the object to an array:

var collection = FirebaseFirestore.instance.collection('collection');
collection 
    .doc('document_id') // <-- Document ID
    .set({'data': FieldValue.arrayUnion(list)}) // <-- Add data
    .then((_) => print('Added'))
    .catchError((error) => print('Add failed: $error'));

score 2 · Answer 4 · answered May 10 '20 at 13:53

This is a working function I built that adds new Maps to an array in my Firestore Services class. I'm using Json Serializable to annotate all my model classes. userTemplateSections is a data field in my userTemplate firestore documents. I take userTemplate as a constructor of the 'addUserTemplateSection' function to make sure I'm editing the correct document.

I also added the function I made to delete Maps from a firestore document array.

'''

Future<void> addUserTemplateSection(
      {UserTemplate userTemplate, String title, String summary}) async {
    try {
      final UserTemplateSection userTemplateSection =
          UserTemplateSection(title: title, summary: summary);
      await _firestore
          .document(FirestorePath.userTemplate(uid, userTemplate.id))
          .updateData(
        {
          'userTemplateSections':
              FieldValue.arrayUnion([userTemplateSection.toJson()])
        },
      );
    } catch (e) {
      print(e);
    }
  }

'''

Future<void> deleteUserTemplateSection({
    UserTemplate userTemplate,
    UserTemplateSection userTemplateSection,
  }) async {
    try {
      await _firestore
          .document(FirestorePath.userTemplate(uid, userTemplate.id))
          .updateData(
        {
          'userTemplateSections':
              FieldValue.arrayRemove([userTemplateSection.toJson()])
        },
      );
    } catch (e) {
      print(e);
    }
  }

'''

flutter firestore, add new object in array

4 Answers4

Null safe code:

Linked

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