I'm studying RXSwift, and I'm a little confuse about Observables. I've understood the theory, that it can emit events "over time". But, I must initialize it with a value, subscribe, and user that value (which is pointless), but I cannot change the value of that observable later, so, whats the point of saying that it can emit values "over time"??? Can someone clarify it to me? Thanks a lot!
It's true that you can't change the value of an Observable directly because that's not the point of having an Observable. In that case you can just return a value and mutate it inline without using observable.
Think of observable simply as a sequence of events ordered by time. On a sequence data structure you're not directly manipulating / mutating what's inside them, what you do normally is to map them into something else, filter the events that you want to exclude based on a certain condition, or combine them with another sequence.
For example, you can map these events which can be described as e(t), with the horizontal line represents the flow of time.
--1--2--3--4--5--6--|
into its multiples:
func duplicate(event: Int) -> Int {
return event * 2
}
--2--4--6--8--10--12--|
afterwards, filter them
func clip(event: Int) -> Int {
return event < 10
}
--2--4--6--8--|
Then, think of these sequences as any kind of sequence, it can be a result of multiple HTTP responses from multiple requests that you chain together.
It can be a Void that usually results from a UIControl event. You can take a look at the documentation here:
ControlProperty / ControlEvent
However if you really need mutation, take a look at BehaviorRelay.