How to decrease a value using FieldValue in Firestore (SWIFT)?

Question

Reading a blog post and the docs, I found that we can increment a value using FieldValue but I cound't find a decrement function.

document("fitness_teams/Team_1").
  updateData(["step_counter" : FieldValue.decrement(500)]) //Does not exist

To decrement a value we still need to use transactions?

Answer 1

There is no need for a decrement function, simply pass a negative value to the actual increment() function:

document("fitness_teams/Team_1").
  updateData(["step_counter" : FieldValue.increment(-500)])

And the value of your step_counter field will be decremented by 500.