An `EventEmitter` is a construct owned by Angular that should be
used for outputs as of right now.
As we are introducing the new `OutputRef` interface for the new output
function APIs, we also think `EventEmitter` should implement
`OutputRef`— ensuring all "known" outputs follow the same contract.
This commit ensures `EventEmitter` implements an `OutputRef`
Note: An output ref captures the destroy ref from the current injection
context for clean-up purposes. This is also done for `EventEmitter` in a
backwards compatible way:
- not requiring an injection context. EventEmitter may be used
elsewhere.
- not cleaning up subscriptions/completing the emitter when the
directive/component is destroyed. This would be a change in behavior.
Note 2: The dependency on `DestroyRef` causes it to be retained in all
bundling examples because ironically `NgZone` uses `EventEmitter`- not
for outputs. The code is pretty minimal though, so that should be
acceptable.
`EventEmitter` will now always retain `NgZone. This increases the
payload size slightly around 800b for AIO. Note that the other increases
were coming from previous changes. This commit just pushed it over the
threshold.
PR Close#54650
A model signal is technically an output, at runtime and conceptually.
This commit re-uses the shared output ref logic and ensures the
interfaces match.
PR Close#54650
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
This commit exposes the new `output()` API with numerous benefits:
- Symmetrical API to `input()`, `model()` etc.
- Fixed types for `EventEmitter.emit`— current `emit` method of
`EventEmitter` is broken and accepts `undefined` via `emit(value?: T)`
- Removal of RxJS specific concepts from outputs. error channels,
completion channels etc. We now have a simple consistent
interface.
- Automatic clean-up of subscribers upon directive/component destory-
when subscribed programmatically.
```ts
@Directive({..})
export class MyDir {
nameChange = output<string>(); // OutputEmitterRef<string>
onClick = output(); // OutputEmitterRef<void>
}
```
Note: RxJS custom observable cases will be handled in future commits via
explicit helpers from the interop.
PR Close#54650
This refactor makes it easier to update the return types of guards.
Rather than having to track what types guards can return, which may
change with new features over time, `MaybeAsync<GuardResult>` can be
used instead.
PR Close#54580
Angular has the `@Attribute` decorator that allows for attributes to be injected from the host node, but we don't have an equivalent for the `inject` function. These changes introduce the new `HostAttributeToken` class that can be used to inject attributes similarly to `@Attribute`. It can be used as follows:
```typescript
import {HostAttributeToken, inject} from '@angular/core';
class MyDir {
someAttr = inject(new HostAttributeToken('some-attr'));
}
```
The new API works similarly to `@Attribute` with one key exception: it will throw a DI error when the attribute doesn't exist, instead of returning `null` like `@Attribute`. We made this change to align its behavior closer to other injection tokens.
PR Close#54604
Add an image loader for Netlify Image CDN. It is slightly different in implementation from existing loaders, because it allows absolute URLs
Fixes#54303
PR Close#54311
Fixes that `ɵunwrapWritableSignal` inferring getter functions as not matching the interface of `WritableSignal` instead of preserving them.
PR Close#54252
In a previous commit the TCB was changed to cast the assignment to an input in order to widen its type to allow `WritableSignal`. This ended up breaking existing inputs whose setter has a wider type than its getter. These changes switch to unwrapping the value on the binding side.
PR Close#54252
Adds support for model inputs in the framework. `model()` returns a writable signal that implicitly defines a input/output pair that can be used either in two-way bindings to keep two values in sync or by binding individually to the input and output. When the value of the `model` changes, it will emit an event with the current value.
Furthermore, these changes expand two-way bindings to accept `WritableSignal`. This will make it easier to transition existing code to signals in a backwards-compatible way.
Example:
```ts
@Directive({
selector: 'counter',
standalone: true,
host: {
'(click)': 'increment()',
}
})
export class Counter {
value = model(0);
increment(): void {
this.value.update(current => current + 1);
}
}
@Component({
template: `<counter [(value)]="count"/> The current count is: {{count()}}`,
})
class App {
count = signal(0);
}
```
PR Close#54252
This commit improves IDE completion of the `read` option for
signal-based queries.
Currently, TS only matches the first overload when starting out with
defining a query. TS doesn't build up the combination of possible
options from the second overload- so in practice users will only see
IDE completions for the `descendants` option.
This is not a problem for view queries as the only option is `read`, so
TS will always match the overload with the `read` option.
```
class X {
query = contentChild('', {^^ <--
here we should completion for `read` an `descendants`
}
```
PR Close#54280
A single error code is created to unify the common error pattern in local compilation mode where an imported const cannot be resolved, but needs to be resolved. This mainly happens for Angular decorator fields such as @Component.template.
The error messages are also upgraded to be more centered around this unifying theme.
PR Close#54230
This commit changes the approach to the reactive node representing query
results: instead of creating a custom node type we can use a computed -
the main change to get there is representing dirty change notification as
a signal (a counter updated every time a query changes its dirty status).
This change is dictated by simplification (we can avoid creation of a custom
signal type) as well as fixes to the multiple issues not covered by the
initial implementation:
- assuring referential stability of results (ex.: the same array instance
returned from child queries until results change);
- per-view results collection to avoid a situation where accessing query
results during view creation would return partial / inconsistent results;
- proper refresh of query results for both live and non-connected consumers.
All the above cases are covered by the additional tests in this commit.
PR Close#54103
As we are introducing the new `output()` function as an inituive
alternative to `@Output()` that matches with signal-based inputs,
this commit prepares the compiler to detect such initializer-based
outputs.
PR Close#54217
This commit includes a skeleton of how the tool `LocalCompilationExtraImportsTracker` is used in the overall compilation workflow end-to-end.
First of all, a new option `generateExtraImportsInLocalMode` is added, whose presence will make `LocalCompilationExtraImportsTracker` part of the compilation process. When this option is set an instance of `LocalCompilationExtraImportsTracker` is created within the NgCompiler. Then it is passed to the Ivy transformer and plumbed all the way down and the extra imports registered in it are added to the `ImportManager` instances before the imports are added from `ImportManager` to the generated file. This required adding a new method `generateSideEffectImport` to the `ImportManager`, which is an empty method and will be implemented in the subsequent commits.
This commit expected to make no change in the compilation behavior as the methods are not implemented yet.
PR Close#53543
When the zoneless scheduler is provided, we want to update the behavior
of `ComponentFixture` to address common issues and painpoints in testing.
Developers should never have to call `detectChanges` on a fixture
manually. Instead of calling `detectChanges` after performing an
action that updates state and requies a template refresh, developers
should wait for change detection to run because the update needs to also have
notified the scheduler. If this was not the case, the component would
not work correctly in the application. Calling `detectChanges` to force
an update could hide real bugs.
This commit also updates the zoneless tests to uses `ComponentFixture`
instead of manually attaching to the `ApplicationRef` and rewriting a
lot of the helpers (`getDebugNode`, `isStable` as a value, `whenStable` as a
Promise).
PR Close#54024
This commit separates `InputSignal` for input signals with transforms.
The reason being that most of the time, signal inputs are not using
transforms and the generics are rather confusing.
Especially for users with inferred types displayed in their IDEs, the
input signal types are seemingly complex, even if no transform is used.
For this reason, we are introducing a new type called
`InputSignalWithTransform`. This type will be used for inputs with
transforms, while non-transform inputs just use `InputSignal`.
A notable fact is that `InputSignal` extends `InputSignalWithTransform`,
with the "identity transform". i.e. there is no transform. This allows
us to share the code for input signals. In practice, we don't expect
users to pass around `InputSignal`'s anyway.
PR Close#54053
The Template Pipeline is a brand new backend for the Angular compiler, replacing `TemplateDefinitionBuilder`. It generates the Ivy instructions corresponding to an input template (or host binding). The Template Pipeline has an all-new design based on an intermediate representation compiled over many phases, which will allow us to experiment with compiler changes more easily in the future.
With this commit, the template pipeline can now be enabled in any project via the `useTemplatePipeline` TSConfig option. However, it is still disabled by default.
PR Close#54057
This commit introduces three additional diagnostics for queries:
- If a query (either using decorator or signal-based) is declared on a
static class member, a diagnostic is raised.
- If a signal-based query is mixed with a query decorator, a diagnostic
is raised. Similar to signal inputs.
- If a singal-based query is also declared in the directive/component
class decorator metadata, a diagnostic is raised.
PR Close#54019
At the moment local compilation breaks for host directives because the current logic relies on global static analysis. This change creates a local version by cutting the diagnostics and copying the directive identifier as it is to the generated code without attempting to statically resolve it.
PR Close#53877
Enables signal inputs for existing Zone based components.
This is a next step we are taking to bring signal inputs earlier to the Angular community.
The goal is to enable early access for the ecosystem to signal inputs, while we are continuing
development of full signal components as outlined in the RFC. This will allow the ecosystem
to start integrating signals more deeply, prepare for future migrations, and improves code quality
and DX for existing components (especially for OnPush).
Based on our work on full signal components, we've gathered more information and learned
new things. We've improved the API by introducing a way to intuitively declare required inputs,
as well as improved the API around initial values. We even support non-primitive initial values
as the first argument to the `input` function now.
```ts
@Directive({..})
export class MyDir {
firstName = input<string>(); // string|undefined
lastName = input.required<string>(); // string
age = input(0); // number
```
PR Close#53872
Currently when someone declares a signal or non-signal input on a static
class member, the compiler will not yield any diagnostic. We can detect
these mistakes and report a diagnostic to help our users.
PR Close#53808
This commit addds two diagnostics for two scenarios where signal inputs
are declared incorrectly:
- a signal input is also annotated with `@Input` in the TypeScript
sources.
- a signal input is also declared in the `inputs` option of
`@Directive/`@Component`.
PR Close#53808
Whenever a required input is accessed too early in a
directive/component, the signal input will throw an error.
This is necessary so that we can support required inputs
with intuitive typings that do not include `undefined` for
the short period of time where Angular is creating the component and
then assigning inputs later (Angular currently has no way of setting
inputs as part of the class creation when `new Dir()` happens)
PR Close#53808
The `afterRender` hooks currently run after `ApplicationRef.tick` but
also run after any call to `ChangeDetectorRef.detectChanges`. This is
problematic because code which uses `afterRender` cannot expect the
component it's registered from to be rendered when the callback
executes. If there is a call to `ChangeDetectorRef.detectChanges` before
the global change detection, that will cause the hooks to run earlier
than expected.
This behavior is somewhat of a blocker for the zoneless project. There
is plenty of application code that do things like `setTimeout(() =>
doSomethingThatExpectsComponentToBeRendered())`, `NgZone.onStable(() =>
...)` or `ApplicationRef.onStable...`. `ApplicationRef.onStable` is a
should likely work similarly, but all of these are really wanting an API
that is `afterRender` with the requirement that the hook runs after the
global render, not an individual CDRef instance.
This change updates the `afterRender` hooks to only run when
`ApplicationRef.tick` happens.
fixes#52429fixes#53232
PR Close#52455
This is a follow up to 5c1d441029
which added the `info` property to navigation requests. `RouterLink` now
supports passing that transient navigation info to the navigation
request.
This info object can be anything and doesn't have to be serializable.
One use-case might be for passing the element that was clicked. This
might be useful for something like view transitions. In the "animating
with javascript" example from the blog (https://stackblitz.com/edit/stackblitz-starters-cklnkm)
those links could have done this instead of needing to create a separate
directive that tracks clicks.
PR Close#53784
This commit introduces the runtime `InputSignal` implementation.
Input initializers using `input` or `input.required` will result in
an instance of `InputSignal` to be created.
An input signal extends the signal primtive, with a couple of small
differences:
- it's a readonly signal. There is no public `set` or `update`.
- equality is non-configurable. As per CD semantics, the value is
guaranteed to be different when the `property` instruction attempts
to update an input signal.
- we support a `transform` function, that allows transforming input
values. The transform is called whenever the input is set. An
alternative could have been to follow computed-semantics and call the
transform upon accessing, if dirty.
In the future, we might change this to extend the computed reactive
node, so that we can support computed inputs that do not rely on
continious bound value assignments. See signal based components RFC.
PR Close#53571
For the implementation of input signals, we want to extend the signal
primitive. The basic methods exposed here are not suitable as we'd like
to store additional metadata on the reactive node, and also have a
custom getter (for required inputs and throwing).
To enable this, one small piece was missing. This commit exposes it and
also improves type safety, now that `SignalNode` is typed properly after
the previous commit.
PR Close#53571
The `SignalNode` interface, describing the reactive node for a `Signal`,
seemingly exposes the `SIGNAL` symbol as a class member. This is not
true as the `SIGNAL` reactive node only exists on the getter function,
as a way to retrieve the signal underlying reactive node.
This commit fixes this, enabling improved type-safety later, in a
follow-up commit where `SIGNAL_NODE` can now be typed to match the
`SignalNode` interface (unlike now where it's typed as just `object`).
PR Close#53571
