How to delete multiple documents with specific Value in Firestore with Flutter

Question

I'm trying to delete multiple docs whith a specific String value in a Field from my collection. But im doing something wrong I think.

onPressed: () async {
  Firestore.instance.collection('collection').getDocuments().then((snapshot) {
  for (DocumentSnapshot ds in snapshot.documents.where(('field') == 'specificValue'){
    ds.reference.delete();
    });
  });
}

Im currently trying to delete each Item with a loop after getting all documents, but im not able to delecte the specific Items. Because I'm getting an error under the "where" part.

Solution

To use where, you'll need to get the list of all the docs in that collection, then where to filter the List and delete the filteredList

  onPressed: () async {
    onPressed() async {
    Firestore.instance.collection('collection').getDocuments().then((snapshot) {
      List<DocumentSnapshot> allDocs = snapshot.documents;
      List<DocumentSnapshot> filteredDocs =  allDocs.where(
              (document) => document.data['field'] == 'specificValue'
      ).toList();
      for (DocumentSnapshot ds in filteredDocs){
        ds.reference.updateData({
          'field': 'newValue'
        });
      }
    });
  }

Comments

[Kinnay]

Hey, your function works great. But i noticed that it would be better to set the value "filed" to null for each document, instead of deleting them. Is it possible to do this with a updateData() function instead of the delete() function? When yes how can i only uopdate this one Field Value.

[JideGuru]

Ohh 'filed' is a type. it's meant to be 'field'