How to delete a field in Firestore document with flutter

I think this is currently impossible in standard, non hacky way. There is an open issue https://github.com/flutter/flutter/issues/13905 in Flutter which have to be resolved first.

Update Oct,2018: This is Now Possible:

In order to delete a particular field from a Cloud Firestore document - make sure you are using Plugin version 0.8.0 or Above. Now a E.g If you have a document having a field 'Desc' with contain some Text. In Order to Delete it.

Firestore.instance.collection('path').document('name').update({'Desc': FieldValue.delete()}).whenComplete((){
  print('Field Deleted');
});

This will Delete 'Desc' Field from the Document 'name'