CODEWITHSUNDEEP
androidkotlinkotlin-flow
yazan sayed
yazan sayed

Reputation: 1139

update a MutableStateFlow when another MutableStateFlow emits

val persons = MutableStateFlow<List<Person>>(emptyList())
val names = MutableStateFlow<List<String>>(emptyList())

I want to update names whenever persons emits a new value. This could be done by observing persons like:

viewModelScope.launch{
  persons.collectLatest{personList->
    names.emit(personList.map{it.name})
  }
}

but I was wondering if there is another way to achieve that, e.g. using flow operators ?

Upvotes: 0

Views: 105

Answers (1)

Arthur Saverest
Arthur Saverest

Reputation: 44

Looks a little nicer

persons.map{ persons ->
    names.emit(persons.map{ it.name })
}.launchIn(viewModelScope)

If there is no need for reactive actions, then a function can be used.

val names = {
    persons.map{
        it.name
    }
}
// call
println(names())

If it's a class property, even better

val names: String
    get() = persons.map{it.name}

Upvotes: 1

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