WritableSignal

Signal propagates only if its value has changed

Subscribe an external observer to this observable

A stream of all values in this signal, excluding the initial value.

When re-starting this stream, it emits the signal's new current value if and only if something has caused the signal's value to be updated or re-evaluated while the changes stream was stopped. This way the changes stream stays in sync with the signal even after restarting.

See also debug methods in com.raquo.airstream.debug.DebuggableObservable

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

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

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

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) by reference equality (eq)

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

Distinct all values (both events and errors) 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).

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

Total number of internal and external observers

Add a noop observer to this signal to ensure that it's started. This lets you access .now and .tryNow on the resulting StrictSignal.

You can use myStream.toWeakSignal.observe.tryNow() to read the last emitted value from event streams just as well.

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

A signal that emits the accumulated value every time that the parent signal emits.

A signal that emits the accumulated value every time that the parent signal emits.

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

Unwrap Try to "undo" recoverToTry – Encode Failure(err) as observable errors, and Success(v) as events

Override defaultDisplayName instead of this, if you need to.

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

Note: Observer can be added more than once to an Observable. If so, it will observe each event as many times as it was added.

Note: This is enforced to be a Set outside of the type system #performance