BaseObservable

Subscribe an external observer to this observable

Create a new observable that listens to this one and has a debugger attached.

Use the resulting observable in place of the original observable in your code. See docs for details.

There are more convenient methods available implicitly from DebuggableObservable and DebuggableSignal, such as debugLog(), debugSpyEvents(), etc.

Distinct all values (both events and errors) using a comparison function

Convert this to an observable that emits Left(err) instead of erroring

Convert this to an observable that emits Failure(err) instead of erroring

Distinct events (but keep all errors) by == (equals) comparison

Distinct events (but keep all errors) by matching key Note: key(event) might be evaluated more than once for each event

Distinct events (but keep all errors) using a comparison function

Distinct events (but keep all errors) by reference equality (eq)

Distinct errors only (but keep all events) using a comparison function

Airstream may internally use Scala library functions which use == or hashCode for equality, for example List.contains. Comparing observables by structural equality pretty much never makes sense, yet it's not that hard to run into that, all you need is to create a case class subclass, and the Scala compiler will generate a structural-equality equals and hashCode methods for you behind the scenes.

To prevent that, we make equals and hashCode methods final, using the default implementation (which is reference equality).

#WARNING: DO NOT USE THIS METHOD. See https://github.com/raquo/Airstream/#flattening-observables

Alias to flatMapSwitch(_ => s)

Based on flatMapSwitch, but tracks the status of input and output to flatMap. See Status.

Shorthand for flatMapWithStatus(_ => innerStream).

Create an external observer from a function and subscribe it to this observable.

Note: since you won't have a reference to the observer, you will need to call Subscription.kill() to unsubscribe

Force reference equality checks. See comment for equals.

value is passed by name, so it will be evaluated whenever the Observable fires. Use it to sample mutable values (e.g. myInput.ref.value in Laminar).

See also: mapToStrict

value is evaluated strictly, only once, when this method is called.

See also: mapTo

Execute a side effecting callback every time the observable emits. If it's a signal, it also runs when its initial value is evaluated.

Note: some signals such as stream.startWith or signal.composeAll have cacheInitialValue config, which could affect the number of times this callback is called in cases when you re-start a signal that was previously started, but has never emitted events before. In such cases, if cacheInitialValue == false (the default) , it will cause the signal's initial value to be re-evaluated, and this will in turn trigger the provided tapEach callback.

See com.raquo.airstream.misc.SignalFromStream

// #TODO[API] How to better type this? Note: Do not provide a callback that returns a LAZY value such as EventStream, it will not be started. I may eventually add a flatTapEach method for this.

Note: Calling tapEach on an observable does not add observers to it. The callback will only run if something else is listening to the observable.

Note: The primary method of running side effects in Airstream is putting them into Observers. In general, it's good practice to keep Observables themselves free of side effects. Airstream is actually pretty good at handling non-"pure" observables, but it's better to have such separation of concerns for your own sanity and the code's predictability / maintainability.

Note: This method is called tapEach for consistency with Scala collections. Scala also has a general tap method available by importing util.chaining.*.

Convert this observable to a signal of Option[A]. If it is a stream, set initial value to None.

This is the method that subclasses override to preserve the user's ability to set custom display names.

Set the display name for this instance (observable or observer).

• This method modifies the instance and returns this. It does not create a new instance.
• New name you set will override the previous name, if any. This might change in the future. For the sake of sanity, don't call this more than once for the same instance.
• If display name is set, toString will output it instead of the standard type@hashcode string

Override defaultDisplayName instead of this, if you need to.