Firestore update

https://firebase.google.com/docs/firestore/manage-data/add-data#update-data

set vs update

The way I understood the difference:

• set without merge will overwrite a document or create it if it doesn't exist yet

• set with merge will update fields in the document or create it if it doesn't exists

• update will update fields but will fail if the document doesn't exist

• create will create the document but fail if the document already exists

There's also a difference in the kind of data you provide to set and update.

For set you always have to provide document-shaped data:

set(
  {a: {b: {c: true}}},
  {merge: true}
)

With update you can also use field paths for updating nested values:

update({
  'a.b.c': true
})

from Difference between set with {merge: true} and update