How to update Map Value in Flutter Firebase Firestore

Question

I have a Map object in my document data. Like Below

I have to add a new user bid to the same map without erasing old data but the code I used was replacing the whole Map with the new value. Any suggestions on how to achieve my goal.

FirebaseFirestore.instance.collection('products')
.doc(widget.product.uid).update({
  'bids': {
  auth.currentUser?.email:
      currentPrice.toString()
  }
});

Ok that means, I have to update Map myself and then add it to firestore. Is it ? — Swaroop Maddu
– Swaroop Maddu, Commented Jul 18, 2021 at 7:39

Dharmaraj · Accepted Answer · 2021-07-18 09:36:38Z

8

You need to use dot notation to update a nested field:

const userEmail = auth.currentUser?.email;
FirebaseFirestore.instance.collection('products')
.doc(widget.product.uid).update({
  'bids.${userEmail}':  currentPrice.toString()
});

Dot notation allows you to update a single nested field without overwriting other nested field. If you update a nested field without dot notation, you will overwrite the entire map field

References:

To update fields with . in their keys:

var fPath = FieldPath(["bids", "[email protected]"]);
FirebaseFirestore.instance.collection('products').doc(widget.product.uid).update(fPath, currentPrice.toString());

edited Jul 18, 2021 at 9:36

answered Jul 18, 2021 at 7:45

Dharmaraj

51.3k8 gold badges67 silver badges100 bronze badges

Sign up to request clarification or add additional context in comments.

6 Comments

Matteo Antolini Over a year ago

Definitely more efficient than my solution. Use this

Dharmaraj Over a year ago

@MadduSwaroop can you share your updated code? Also try restarting your emulator or app. Using dot notation should update that field only and not overwrite others. It's mentioned in both Firebase's docs and FlutterFire's.

Swaroop Maddu Over a year ago

Sorry I forgot to save : ) My bad.

Swaroop Maddu Over a year ago

You are simply awesome Thanks for the help.

Swaroop Maddu Over a year ago

Bro this time another map was creating inside bids because of . in mail id? Any way to avoid it

|

Collectives™ on Stack Overflow

How to update Map Value in Flutter Firebase Firestore

1 Answer 1

6 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

6 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related