Producers represent values which can deliver change notifications.
When a producer value is changed, a change notification is propagated through the graph,
notifying live consumers which depend on the producer of the potential update.
Note here that this is a _potential_ update.
A producer may not have actually "changed" based on its equality function. With
this commit, before refreshing a view that is only marked for refresh
because its consumer is dirty, we poll producers for change to see if
they really have. If not, we can skip the refresh. The example test in this commit
shows that a `computed` which depends on a `signal` that is updated but
produces a value that is the same as before will _not_ cause the
component's template to refresh.
fixes#51797
PR Close#52476
When an effect is created in a component constructor, it might read signals
which are derived from component inputs. These signals may be unreliable or
(in the case of the proposed input signals) may throw if accessed before the
component is first change detected (which is what makes required inputs
available).
Depending on the scenario involved, the effect may or may not run before
this initialization takes place, which isn't a great developer experience.
In particular, effects created during CD (e.g. via control flow) work fine,
as do effects created in bootstrap thanks to the sync CD it performs. When
an effect is created through dynamic component creation outside of CD though
(such as on router navigations), it runs before the component is first CD'd,
causing the issue.
In fact, in the signal components RFC we described how effects would wait
until ngOnInit for their first execution for exactly this reason, but this
behavior was never implemented as it was thought our effect scheduling
design made it unnecessary. This is true of the regular execution of effects
but the above scenario shows that *creation* of the effect is still
vulnerable. Thus, this logic is needed.
This commit makes effects sensitive to their creation context, by injecting
`ChangeDetectorRef` optionally. An effect created with an injector that's
tied to a component will wait until that component is initialized before
initially being scheduled. TestBed effect flushing is also adjusted to
account for the additional interaction with change detection.
PR Close#52473
This commit splits the `render3/instructions/defer.ts` file (that contained most of the runtime code) into smalle
r files that are easier to maintain.
There are no functional changes in this PR, just organizing code.
PR Close#52152
The flag `forbidOrphanRendering` is only set for non-standalone components, and indicates that the dev mode runtime should through error if the component is rendered without its ngModule loaded in the browser. This runtime error can help with further debugging.
PR Close#52061
A new field `debugInfo` is added to the component definition. Now the runtime ɵsetClassDebugInfo stores the debug info for components in this new field.
PR Close#51919
This commit updates the tracking of dirty child views to be a flag
rather than a counter. This is a much more simple method and less likely
to get into the same 'always-wrong' situation that could happen with the
counter (if it is off by 1 once, it's off by 1 forever and you either
get infinite change detection or your view is never refreshed).
PR Close#51515
This commit adds runtime code to support `after` and `minimum` parameters in the `@placeholder` and `@loading` blocks. The code uses the `TimerScheduler` service added earlier for `on timer` triggers.
PR Close#52009
Currently, if there are 2 nested @defer blocks with the same dependency, Angular throws an error at runtime to indicate that there was a duplicate component def in the registry. This commit updates the logic to only append dependencies when they didn't previously exist in the registry.
PR Close#51964
When adding a new view flag, you currently need to adjust the last number of the last
3 flags. All of these share the same number so the shifting ones can just use
the base-10 IndexWithinInitPhaseShift.
PR Close#51839
Switches the syntax for blocks from `{#block}{/block}` to `@block {}` based on the feedback from the community.
Read more about the decision-making process in our blog: https://blog.angular.io/meet-angulars-new-control-flow-a02c6eee7843
The existing block types changed in the following ways:
**Conditional blocks:**
```html
<!-- Before -->
{#if cond}
Main content
{:else if otherCond}
Else if content
{:else}
Else content
{/if}
<!-- After -->
@if (cond) {
Main content
} @else if (otherCond) {
Else if content
} @else {
Else content
}
```
**Deferred blocks**
```html
<!-- Before -->
{#defer when isLoaded}
Main content
{:loading} Loading...
{:placeholder} <icon>pending</icon>
{:error} Failed to load
{/defer}
<!-- After -->
@defer (when isLoaded) {
Main content
} @loading {
Loading...
} @placeholder {
<icon>pending</icon>
} @error {
Failed to load
}
```
**Switch blocks:**
```html
<!-- Before -->
{#switch value}
{:case 1}
One
{:case 2}
Two
{:default}
Default
{/switch}
<!-- After -->
@switch (value) {
@case (1) {
One
}
@case (2) {
Two
}
@default {
Default
}
}
```
**For loops**
```html
<!-- Before -->
{#for item of items; track item}
{{item.name}}
{:empty} No items
{/for}
<!-- After -->
@for (item of items; track item) {
{{item.name}}
} @empty {
No items
}
```
PR Close#51891
This commit adds the necessary mechanisms to perform cleanup of prefetch triggers when resource loading starts. Previously, this logic was missing, which resulted in retaining those triggers.
PR Close#51856
This change contains runtime logic needed to flatten the NgModule bootstrap field in local compilation mode. While it is quite odd to pass a "nested" array as NgModule bootstrap, it is still required to support this case in local compilation mode since it is supported in full compilation mode.
PR Close#51767
This change flattens the imports/exports/declarations info on ngModule decorators in runtime dev mode by adding flattening logic to the runtime `ɵɵsetNgModuleScope`. Such flattening has no effect in AoT full compilation mode since these arrays are already resolved and flattened by AoT static analysis, but in local compilation mode it is needed since the raw array as appears on the NgModule decorator will be passed to the runtime `ɵɵsetNgModuleScope`, and so it needs to be flattened.
This change has to effect on prod runtime as `ɵɵsetNgModuleScope` is not used in prod.
PR Close#51767
Currently internally Angular has some customized tsconfig files, because we don't align with the tsconfig of the rest of g3. These changes enable `noImplicitReturns` and `noPropertyAccessFromIndexSignature` to align better with the internal config.
PR Close#51728
Previously effects were queued as they became dirty, and this queue was
flushed at various checkpoints during the change detection cycle. The result
was that change detection _was_ the effect runner, and without executing CD,
effects would not execute. This leads a particular tradeoff:
* effects are subject to unidirectional data flow (bad for dx)
* effects don't cause a new round of CD (good/bad depending on use case)
* effects can be used to implement control flow efficiently (desirable)
This commit changes the scheduling mechanism. Effects are now scheduled via
the microtask queue. This changes the tradeoffs:
* effects are no longer limited by unidirectional data flow (easy dx)
* effects registered in the Angular zone will trigger CD after they run
(same as `Promise.resolve` really)
* the public `effect()` type of effect probably isn't a good building block
for our built-in control flow, and we'll need a new internal abstraction.
As `effect()` is in developer preview, changing the execution timing is not
considered breaking even though it may impact current users.
PR Close#51049
This commit updates the logic to add `prefetch on idle` support for defer blocks. Previously, the `on idle` logic was already implemented for the main loading and rendering. This commit reuses the same logic to bring it to the prefetching mechanism.
PR Close#51629
This commit updates the runtime implementation of defer blocks to avoid their triggering on the server. This behavior was described in the RFC (https://github.com/angular/angular/discussions/50716, see "Server Side Rendering Behavior" section): only a placeholder is rendered on the server at this moment. This commit also updates the logic to make sure that the placeholder content is hydrated after SSR.
PR Close#51530
This commit adds an initial implementation of the `{#defer}` block runtime, which supports the `when` conditions. More conditions and basic prefetching support will be added in followup PRs.
PR Close#51347
The runtime `ɵɵsetNgModuleScope` is modified to accept raw scope info as passed to it in local compilation mode. The runtime further registers the ng-module in the deps tracker. Then the runtime `ɵɵgetComponentDepsFactory` is implemented to use the deps tracker to get the component dependencies which leads to a valid and working Angular code.
PR Close#51377
The runtime `ɵɵsetNgModuleScope` is modified to accept raw scope info as passed to it in local compilation mode. The runtime further registers the ng-module in the deps tracker. Then the runtime `ɵɵgetComponentDepsFactory` is implemented to use the deps tracker to get the component dependencies which leads to a valid and working Angular code.
PR Close#51309
An empty runtime is added just to make the local compiled angular files valid to run. A separate PR will implement the runtime in the right way using the deps tracker.
PR Close#51089
The types and interfaces re;ated to the runtime deps tracker are added. Also an empty implementation is added to be completed in follow up PRs (after the interfaces are confirmed in this PR).
The added files are not used anywhere, so the change should not affect anything in anyway.
PR Close#50606
This commit updates an internal hydration logic to make sure that the content of components with i18n blocks is cleaned up before we start rendering it.
Resolves#50627.
PR Close#50644
According to the HTML specification most attributes are defined as strings, however some can be interpreted as different types like booleans or numbers. [In the HTML standard](https://html.spec.whatwg.org/multipage/common-microsyntaxes.html#boolean-attributes), boolean attributes are considered `true` if they are present on a DOM node and `false` if they are omitted. Common examples of boolean attributes are `disabled` on interactive elements like `<button>` or `checked` on `<input type="checkbox">`. Another example of an attribute that is defined as a string, but interpreted as a different type is the `value` attribute of `<input type="number">` which logs a warning and ignores the value if it can't be parsed as a number.
Historically, authoring Angular inputs that match the native behavior in a type-safe way has been difficult for developers, because Angular interprets all static attributes as strings. While some recent TypeScript versions made this easier by allowing setters and getters to have different types, supporting this pattern still requires a lot of boilerplate and additional properties to be declared. For example, currently developers have to write something like this to have a `disabled` input that behaves like the native one:
```typescript
import {Directive, Input} from '@angular/core';
@Directive({selector: 'mat-checkbox'})
export class MatCheckbox {
@Input()
get disabled() {
return this._disabled;
}
set disabled(value: any) {
this._disabled = typeof value === 'boolean' ? value : (value != null && value !== 'false');
}
private _disabled = false;
}
```
This feature aims to address the issue by introducing a `transform` property on inputs. If an input has a `transform` function, any values set through the template will be passed through the function before being assigned to the directive instance. The example from above can be rewritten to the following:
```typescript
import {Directive, Input, booleanAttribute} from '@angular/core';
@Directive({selector: 'mat-checkbox'})
export class MatCheckbox {
@Input({transform: booleanAttribute}) disabled: boolean = false;
}
```
These changes also add the `booleanAttribute` and `numberAttribute` utilities to `@angular/core` since they're common enough to be useful for most projects.
Fixes#8968.
Fixes#14761.
PR Close#50420
This commit updates hydration logic to support a scenario where a view container that was hydrated and later on projected to a component that skips hydration. Currently, such projected content is extracted from the DOM (since a component that skips hydration needs to be re-created), but never added back, since the current logic treats such content as "already inserted".
Closes#50175.
PR Close#50199
This commit adds an LView flag to indicate that a view is a "signal"
view and updates view creation code to correctly set the flag
based on the declaration component metadata.
PR Close#49988
It's likely that the flag and counters used to track transplanted views
needing a refresh will be reused to signal views as well. The two follow
a similar rule: While the parents might not be "Dirty", there is still a
child/descendant view somewhere that needs to be refreshed during change
detection.
PR Close#50000
The LViewFlags are using manually written 0bxxxxx numbers which can be very hard to read
once there are more than a handful of 0s and 1s. The bit shifting feels a lot more
legible.
PR Close#49987
This commit adds the `signals: boolean` property to the internal
directive/component metadata. This does not add it to the public API
yet, as the feature has no internal support other than compiler
detection.
PR Close#49981
Currently, non-destructive hydration for i18n blocks is not supported (but support is coming!).
This commit updates the serialization logic from throwing an error when it comes across an i18n
block to annotating a component with a skip hydration flag.
PR Close#49722
This commit updates the `effect` primitive and significantly changes the
timing of effect execution.
Previously, effects were scheduled via the microtask queue. This commit
changes effects to run throughout the change detection process instead.
Running effects this way avoids needing additional rounds of change
detection to resolve effects, with the tradeoff that they're harder to use
for model-to-model synchronization (which can be seen as a good thing).
PR Close#49641
This commit consolidates the `RendererFactory` and `Sanitizer` properties
of `LView` onto a single object, the `LViewEnvironment`. These properties
are both set from DI when the root view is created, and not overridden when
child views are created (but inherited from the parent view).
This is a precursor commit to adding the `EffectManager` into the
`LViewEnvironment`.
PR Close#49641
This commit updates the `LView` in Angular to be a `Consumer` of
signals. If a signal is read when executing a template, it marks the
view dirty. In addition, if a signal is read when executing host
bindings, it also marks views dirty.
One interesting thing about signal reads in host bindings
is that they perform a bit better than what we can do with today's
APIs. In order to re-execute host bindings for an `OnPush` component that
might have changed, you would probably inject `ChangeDetectorRef` and call
`markForCheck`. This will mark the _current component_ and parents
dirty. However, host bindings are executed as part of refreshing the
_parent_ so there is really no need to re-execute the current component
if the only thing that changed is the host bindings. When a signal is
read in host bindings, it marks the parent dirty and not the component
that defined the host binding.
Additionally, this commit avoids allocating a full consumer for each
`LView` by re-using a consumer until template execution results in a
signal read. At this point, we assign that consumer to the `LView` and
create a new consumer to "tentatively" use for the future `LView`
template executions.
Co-authored-by: Dylan Hunn <github@dylanhunn.com>
PR Close#49153
This commit adds serialization and hydration logic for content projection.
While hydration for regular elements relies on their location in the TNode tree, the content projection may move elements around, so in order to hydrate them correcty, the runtime needs some extra information. This commit adds a serialization logic that adds element locations (instructions on how to navigate to a particular element from another known location of other element) into the hydration state for the following cases:
- when a TNode is a first element in projection segment (other nodes are linked from that node)
- when a TNode's next sibling is different before and after projection (we serialize extra info about the template-based sibling)
- when a TNode's previous sibling was a content projection (i.e. `<ng-content>` slot), because we can not rely on the previous element in this case (projection happens at a later point)
PR Close#49454
This commit adds serialization and hydration logic for content projection.
While hydration for regular elements relies on their location in the TNode tree, the content projection may move elements around, so in order to hydrate them correcty, the runtime needs some extra information. This commit adds a serialization logic that adds element locations (instructions on how to navigate to a particular element from another known location of other element) into the hydration state for the following cases:
- when a TNode is a first element in projection segment (other nodes are linked from that node)
- when a TNode's next sibling is different before and after projection (we serialize extra info about the template-based sibling)
- when a TNode's previous sibling was a content projection (i.e. `<ng-content>` slot), because we can not rely on the previous element in this case (projection happens at a later point)
PR Close#49454
Adds support for marking a directive input as required. During template type checking, the compiler will verify that all required inputs have been specified and will raise a diagnostic if one or more are missing. Some specifics:
* Inputs are marked as required by passing an object literal with a `required: true` property to the `Input` decorator or into the `inputs` array.
* Required inputs imply that the directive can't work without them. This is why there's a new check that enforces that all required inputs of a host directive are exposed on the host.
* Required input diagnostics are reported through the `OutOfBandDiagnosticRecorder`, rather than generating a new structure in the TCB, because it allows us to provide a better error message.
* Currently required inputs are only supported during AOT compilation, because knowing which bindings are present during JIT can be tricky and may lead to increased bundle sizes.
Fixes#37706.
PR Close#49468
This reverts commit 13dd614cd1.
This breaks a g3 Typescript compilation tests where diagnostics are
expected for a missing input in the component.
PR Close#49467
Adds support for marking a directive input as required. During template type checking, the compiler will verify that all required inputs have been specified and will raise a diagnostic if one or more are missing. Some specifics:
* Inputs are marked as required by passing an object literal with a `required: true` property to the `Input` decorator or into the `inputs` array.
* Required inputs imply that the directive can't work without them. This is why there's a new check that enforces that all required inputs of a host directive are exposed on the host.
* Required input diagnostics are reported through the `OutOfBandDiagnosticRecorder`, rather than generating a new structure in the TCB, because it allows us to provide a better error message.
* Currently required inputs are only supported during AOT compilation, because knowing which bindings are present during JIT can be tricky and may lead to increased bundle sizes.
Fixes#37706.
PR Close#49453
This reverts commit 1a6ca68154.
This breaks tests in google3 which might be depending on private APIs. We
need to update these tests before we can land this PR.
PR Close#49449
Adds support for marking a directive input as required. During template type checking, the compiler will verify that all required inputs have been specified and will raise a diagnostic if one or more are missing. Some specifics:
* Inputs are marked as required by passing an object literal with a `required: true` property to the `Input` decorator or into the `inputs` array.
* Required inputs imply that the directive can't work without them. This is why there's a new check that enforces that all required inputs of a host directive are exposed on the host.
* Required input diagnostics are reported through the `OutOfBandDiagnosticRecorder`, rather than generating a new structure in the TCB, because it allows us to provide a better error message.
* Currently required inputs are only supported during AOT compilation, because knowing which bindings are present during JIT can be tricky and may lead to increased bundle sizes.
Fixes#37706.
PR Close#49304
This commit implements hydration support for view containers, which should make `*ngIf`, `*ngFor` and other structural directive work with hydration.
The logic also respects the `ngSkipHydration` flag and skips hydration in such cases.
PR Close#49382
