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 the `ApplicationRef.isStable` API to account for
pending rendering task. This is needed as once a pending rendering task
is done, new macrotask and microtask could be created which previously caused these not
to be intercepted and thus ignored when doing SSR.
PR Close#50425
Adds the necessary compiler changes to support input transform functions. The compiler output has changed in the following ways:
### Directive handler
The directive handler now extracts a reference to the input transform function and it resolves the type of its first parameter. It also asserts that the type can be referenced in the compiled output and that it doesn't clash with any pre-existing `ngAcceptInputType_` members.
### .d.ts
In the generated declaration files the compiler now inserts an `ngAcceptInputType_` member for each input with a `transform` function. The member's type corresponds to the type of the first parameter of the function, e.g.
```typescript
// foo.directive.ts
@Directive()
export class Foo {
@Input({transform: (incomingValue: string) => parseInt(incomingValue)}) value: number;
}
// foo.directive.d.ts
export class Foo {
value: number;
static ngAcceptInputType_value: string;
}
```
### Type check block
If an input has `transform` function, the TCB will use the type of its first parameter for the setter type. This uses the same infrastructure as the `ngAcceptInputType_` members.
### Directive declaration
The generated runtime directive declaration call now includes the `transform` function in the `inputs` map, if the input is being transformed. The function will be picked up by the runtime in the next commit to do the actual transformation.
```typescript
// foo.directive.ts
@Directive()
export class Foo {
@Input({transform: (incomingValue: string) => parseInt(incomingValue)}) value: number;
}
// foo.directive.js
export class Foo {
ɵdir = ɵɵdefineDirective({
inputs: {
value: ['value', 'value', incomingValue => parseInt(incomingValue)]
}
});
}
```
PR Close#50225
Hydration requires a stable App to run some logic.
With this warning developers will be informed about potential issues encountered when running an unstable app.
Fixes#50285
PR Close#50295
Unlike the current signature where the input argument must a function, this change allows an input of any type to be passed to the `isSignal` function.
PR Close#50035
The `main` bundle fell below the threshold. No actual investigation
was done here because it's a reduction in size, and the AIO size
matches the `AIO-local` size now. This is expected because the latest
RC closely matches the `main` branch (or even is equivalent at this
point).
PR Close#50107
Using `@angular/platform-browser-dynamic` is no longer required for JIT scenarios with Ivy. Instead `@angular/compiler` should be imported instead.
This change is part of the effort to reduce the server bundles sizes, which is needed to support cloud workers.
BREAKING CHANGE:
Users that are using SSR with JIT mode will now need to add `import to @angular/compiler` before bootstrapping the application.
**NOTE:** this does not effect users using the Angular CLI.
PR Close#50064
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
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
Hydration relies on a signal from ZoneJS when it becomes stable inside an application, so that Angular can start serialization process on the server or post-hydration cleanup on the client (to remove DOM nodes that remained unclaimed).
Providing a custom or a "noop" ZoneJS implementation may lead to a different timing of the "stable" event, thus triggering the serialization or the cleanup too early or too late. This is not yet a fully supported configuration.
This commit adds a warning (non-blocking) for those cases.
PR Close#49944
In this mode the compiler generates code based on each individual source file without using its dependencies. This mode is suitable only for fast edit/refresh during development.
PR Close#49846
It might happen that the lifecycle scope represented by DestroyRef becomes
invalid before an onDestroy hook is registered (ex. injector or component
instance got destroyed). In such cases registration of the onDestroy hooks
should no longer be possible.
Fixes#49658
PR Close#49804
The new asReadonly method on the WritableSignal interface makes
it possible to create readonly instance of a writable signal.
Readonly signals can be accessed to read their value,
but can't be changed using set, update or mutate methods.
PR Close#49802
Some libraries could use numbers in headers. this fix prevents Angular from
throwing an error by casting those numerical values into strings.
Fixes#49353
PR Close#49379
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
Previously, since the `HttpXhrBackend` is a singleton, the macrotask was created and completed only for the initial request since it was stored as in property in the class instance. This commit replaces this logic to create a macro task for every XHR request.
Closes#49730
PR Close#49776
This change makes is possible to use async functions
(ones returning a promise) as effect run functions.
To make it possible, the signature of the effect function
changed: effect cleanup function is registered now
(using a dedicated callback passed to the effect creation)
instead of being returned from the effect function.
PR Close#49783
This commit updates the logic to detect a situation when hydration support was enabled only on the client. If that happens, Angular produces a warning in a console with a link to the error guide.
PR Close#49743
In archive mode the link to the current doc will now point to same page.
If the page doesn't exist anymore, it will show a contextualized warning message.
See #46850
PR Close#49063
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
The `TransferState` class was updated in v14 in a way that the `BrowserTransferStateModule` was no longer required. The `BrowserTransferStateModule` was deprecated in v14.1 and it's currently empty. This commit removes the `BrowserTransferStateModule`.
BREAKING CHANGE: The deprecated `BrowserTransferStateModule` was removed, since it's no longer needed. The `TransferState` class can be injected without providing the module. The `BrowserTransferStateModule` was empty starting from v14 and you can just remove the reference to that module from your applications.
PR Close#49718
Previously, attempting to turn off the `experimentalDecorators` TypeScript configuration
option within an Angular project would result in build time errors. These errors were due
to an exposed Decorator signature from `@angular/core` that TypeScript thought was incompatible
with standard decorators. However, Angular's class decorators (`Component`, `Directive`, `Pipe`,
`Injectable`, `NgModule`) are actually already compatible with standard decorators. The export types for
the decorators only needed to be updated to reflect that compatibility. With the updated exported types,
applications will now successfully compile and execute in AOT mode with one important dependency injection
caveat explained in the note below.
For JIT mode applications that are built with the Angular CLI, `@ngtools/webpack`, or use `tsickle`,
there were also no additional changes required. These tools automatically convert property decorators
(now called field decorators) at build time to store Angular property metadata directly on the relevant
class. Building with these tools is the overwhelmingly common method of building an application. Any
applications that do not use one of these tools will not function at runtime in JIT mode if using standard
decorators. The behavior and code for when experimental decorators is enabled has been left intact.
NOTE: Angular constructor dependency injection that requires parameter decorators is not supported.
The standard decorator specification does not support parameter decorators. The `inject` function must be
used for all cases that previously required a parameter decorator. This includes such decorators as `Inject`,
`Optional`, `Self`, `SkipSelf`, `Host`, and `Attribute`. Constructor dependency injection that relies only
on the supplied parameter type will continue to function as expected if using AOT; as well as in JIT mode
if using the Angular CLI, `@ngtools/webpack` directly, or `tsickle`.
Documentation for the `inject` function can be found at: https://angular.io/api/core/inject
The decorator specification proposal can be found at: https://github.com/tc39/proposal-decorators
PR Close#49492
The `ReflectiveInjector` symbol has been deprecated in v5 (11 major versions ago). This commit removes ReflectiveInjector and related symbols.
BREAKING CHANGE: The `ReflectiveInjector` and related symbols were removed. Please update the code to avoid references to the `ReflectiveInjector` symbol. Use `Injector.create` as a replacement to create an injector instead.
PR Close#48103
This commit adds support by default for HTTP caching when using `provideClientHydration`. Users can opt-out of this behaviour by using the `withoutHttpTransferCache` feature.
```ts
import {
bootstrapApplication,
provideClientHydration,
withNoHttpTransferCache,
} from '@angular/platform-browser';
// ...
bootstrapApplication(RootCmp, {
providers: [provideClientHydration(withNoHttpTransferCache())]
});
```
PR Close#49699
This commit adds the `provideClientHydration` function to the public API. This function can be used to enable the non-destructive Angular hydration.
Important note: the non-destructive hydration feature is in Developer Preview mode, learn more about it at https://angular.io/guide/releases#developer-preview.
Before you can get started with hydration, you must have a server side rendered (SSR) application. Follow the [Angular Universal Guide](https://angular.io/guide/universal) to enable server side rendering first. Once you have SSR working with your application, you can enable hydration by visiting your main app component or module and importing `provideClientHydration` from `@angular/platform-browser`. You'll then add that provider to your app's bootstrapping providers list.
```typescript
import {
bootstrapApplication,
provideClientHydration,
} from '@angular/platform-browser';
// ...
bootstrapApplication(RootCmp, {
providers: [provideClientHydration()]
});
```
Alternatively if you are using NgModules, you would add `provideClientHydration` to your root app module's provider list.
```typescript
import {provideClientHydration} from '@angular/platform-browser';
import {NgModule} from '@angular/core';
@NgModule({
declarations: [RootCmp],
exports: [RootCmp],
bootstrap: [RootCmp],
providers: [provideClientHydration()],
})
export class AppModule {}
```
You can confirm hydration is enabled by opening Developer Tools in your browser and viewing the console. You should see a message that includes hydration-related stats, such as the number of components and nodes hydrated.
Co-authored-by: jessicajaniuk <72768744+jessicajaniuk@users.noreply.github.com>
Co-authored-by: alan-agius4 <17563226+alan-agius4@users.noreply.github.com>
PR Close#49666
To match the behaviour of Array.filter, typeguards can now be used on QueryList.filter to narrow the return type.
Fixes#38446
BREAKING CHANGE: QueryList.filter now supports type guard functions, which will result in type narrowing. Previously if you used type guard functions, it resulted in no changes to the return type. Now the type would be narrowed, which might require updates to the application code that relied on the old behavior.
PR Close#48042
