This commit introduces an addition to `output()` and
`outputFromObservable`()` —called `outputToObservable()`.
The helper lives in the RxJS interop package and allows agnostic
programmatic subscriptions to `OutputRef`s by converting the output
to an observable with `.pipe` etc.
The function is ideally used in all places where you subscribe to an
output programmatically. Those outputs in the future, with the new APIs,
may not be actual RxJS constructs, but abstract `OutputRef`'s that
simply expose a `.subscribe` method. The helper allows you to
agnostically convert outputs to RxJS observables that you can safely
interact with.
The observables are also completed automatically, if possible, when the
owning directive/component is destroyed— Something that is not
guaranteed right now.
PR Close#54650
Introduces a second API in addition to the new `output()` function.
The new function `outputFromObservable()` can be used to declare outputs
using the new `OutputRef` API and `output()` API, while using a custom
RxJS observable as data source.
This is something that is currently possible in Angular and we would
like to keep possible- even though we never intended to support custom
observables aside from RxJS-based `EventEmitter`.
The interop bridges the gap and allows you to continue using
`Subject`, `ReplaySubject`, `BehaivorSubjct,` - or cold custom
observables for outputs. You can still trigger logic only when
the output is subscribed- unlike with imperative `emit`s of
`EventEmitter` or the new `OutputEmitterRef`.
A notable difference is that you need two class members where you
previously could access the `Subject` directly. This is an intentional
trade-off we've made to ensure that all new outputs implement the
`OutputRef` interface and we are exposing a minimal API surface to
consumers of components that currently access the output
programmatically.
PR Close#54650
By default, `toSignal` transforms an `Observable` into a `Signal`, including
the error channel of the Observable. When an error is received, the signal
begins throwing the error.
`toSignal` is intended to serve the same purpose as the `async` pipe, but
the async pipe has a different behavior with errors: it rejects them
outright, throwing them back into RxJS. Rx then propagates the error into
the browser's uncaught error handling logic. In the case of Angular, the
error is then caught by zone.js and reported via the application's
`ErrorHandler`.
This commit introduces a new option for `toSignal` called `rejectErrors`.
With that flag set, `toSignal` copies the async pipe's behavior, allowing
for easier migrations.
Fixes#51949
PR Close#52474
This commit cleans up the signatures of `toSignal` to better handle the
types of situations that it might be used in, and produce better type
inference results.
Fixes#50687Fixes#50591
Co-authored-by: Andrew Scott <atscott@google.com>
PR Close#51991
Extend toSignal to accept any Subscribable (instead of only Observable)
for consistency with AsyncPipe and for broader compatibility with any
observable library (that is compatible with the Subscribable interface).
This is only a type change as the implementation does not use anything
else than the Subscribable interface anyway.
PR Close#50162
This commit introduces an interface for `toSignal` options to mirror that of
`toObservable`, and adjusts docs for both symbols. It also adds the ability
for `toSignal` to manually specify `DestroyRef` (similarly to
`toObservable` accepting an injector) or for `toSignal` automatic cleanup to
be disabled (in which case the subscription persists until the Observable
completes). Either option allows `toSignal` to be used outside of a DI
context, like `toObservable`.
PR Close#50071
The initial value used for signals by default is now `undefined`. In
addition, there is a new option to express that the signal should emit a
value synchronously (`requireSync: true`). When this value is specified,
the function will throw _on creation_ if the subscribing to the
`Observable` does not result in a synchronous emit.
PR Close#49769
This commit implements an RxJS operator `takeUntilDestroyed` which
terminates an Observable when the current context (component, directive,
etc) is destroyed. `takeUntilDestroyed` will inject the current `DestroyRef`
if none is provided, or use one provided as an argument.
PR Close#49154
This commit adds the basic sketch for the implementation of `fromObservable`
and `fromSignal`, the two basic primitives which form the RxJS interop layer
with signals.
PR Close#49154
This commit adds the infrastructure for `@angular/core/rxjs-interop`, a new
core entrypoint which provides bidirectional interoperability between
Angular's built-in reactivity system of synchronous signals, and the RxJS
`Observable` abstraction.
The new entrypoint is set up as an empty shell in this commit, with its
implementation to follow in a followup.
PR Close#49154
Paul Gschwendtner