Update fields in nested objects in firestore documents?

Question

I have a data structure like:

I want to edit the value of \"test\" key in \"first\" object. I followed the document on https://firebase.google.com/docs/fire

Answer 1

According to the link you provided, it says this:

If your document contains nested objects, you can use "dot notation" to reference nested fields within the document when you call update():

Therefore you need to use dot notation to be able to update only one field without overwriting, so like this:

var setAda = dbFirestore.collection('users').doc('alovelace').update({
    "first.test": "12345"
});

then you will have:

 first
  test: "12345"
  test2: "abcd"