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/Angular 12

@angular/core

package

Implements Angular's core functionality, low-level services, and utilities.

Defines the class infrastructure for components, view hierarchies, change detection, rendering, and event handling.
Defines the decorators that supply metadata and context for Angular constructs.
Defines infrastructure for dependency injection (DI), internationalization (i18n), and various testing and debugging facilities.

Entry points

Primary

@angular/core

Implements Angular's core functionality, low-level services, and utilities.

Secondary

`@angular/core/global`	Exposes a set of functions in the global namespace which are useful for debugging the current state of your application. These functions are exposed via the global `ng` "namespace" variable automatically when you import from `@angular/core` and run your application in development mode. These functions are not exposed when the application runs in a production mode.
`@angular/core/testing`	Provides infrastructure for testing Angular core functionality.

Primary entry point exports

NgModules

ApplicationModule

Configures the root injector for an app with providers of @angular/core dependencies that ApplicationRef needs to bootstrap components.

Classes

`ApplicationInitStatus`	A class that reflects the state of running `APP_INITIALIZER` functions.
`ApplicationRef`	A reference to an Angular application running on a page.
`Attribute`	Attribute decorator and metadata.
`ChangeDetectorRef`	Base class that provides change detection functionality. A change-detection tree collects all views that are to be checked for changes. Use the methods to add and remove views from the tree, initiate change-detection, and explicitly mark views as dirty, meaning that they have changed and need to be re-rendered.
`Compiler`	Low-level service for running the angular compiler during runtime to create `ComponentFactory`s, which can later be used to create and render a Component instance.
`CompilerFactory`	A factory for creating a Compiler
`ComponentFactory`	Base class for a factory that can create a component dynamically. Instantiate a factory for a given type of component with `resolveComponentFactory()`. Use the resulting `ComponentFactory.create()` method to create a component of that type.
`ComponentFactoryResolver`	A simple registry that maps `Components` to generated `ComponentFactory` classes that can be used to create instances of components. Use to obtain the factory for a given component type, then use the factory's `create()` method to create a component of that type.
`ComponentRef`	Represents a component created by a `ComponentFactory`. Provides access to the component instance and related objects, and provides the means of destroying the instance.
`DebugElement`
`DebugEventListener`
`DebugNode`
`DefaultIterableDiffer`	Deprecated: v4.0.0 - Should not be part of public API.
`ElementRef`	A wrapper around a native element inside of a View.
`EmbeddedViewRef`	Represents an Angular view in a view container. An embedded view can be referenced from a component other than the hosting component whose template defines it, or it can be defined independently by a `TemplateRef`.
`ErrorHandler`	Provides a hook for centralized exception handling.
`EventEmitter`	Use in components with the `@Output` directive to emit custom events synchronously or asynchronously, and register handlers for those events by subscribing to an instance.
`InjectionToken`	Creates a token that can be used in a DI Provider.
`Injector`	Concrete injectors implement this interface. Injectors are configured with providers that associate dependencies of various types with injection tokens.
`IterableDiffers`	A repository of different iterable diffing strategies used by NgFor, NgClass, and others.
`KeyValueDiffers`	A repository of different Map diffing strategies used by NgClass, NgStyle, and others.
`ModuleWithComponentFactories`	Combination of NgModuleFactory and ComponentFactories.
`NgModuleFactory`
`NgModuleFactoryLoader`	Deprecated: the `string` form of `loadChildren` is deprecated, and `NgModuleFactoryLoader` is part of its implementation. See `LoadChildren` for more details. Used to load ng module factories.
`NgModuleRef`	Represents an instance of an `NgModule` created by an `NgModuleFactory`. Provides access to the `NgModule` instance and related objects.
`NgProbeToken`	A token for third-party components that can register themselves with NgProbe.
`NgZone`	An injectable service for executing work inside or outside of the Angular zone.
`PlatformRef`	The Angular platform is the entry point for Angular on a web page. Each page has exactly one platform. Services (such as reflection) which are common to every Angular application running on the page are bound in its scope. A page's platform is initialized implicitly when a platform is created using a platform factory such as `PlatformBrowser`, or explicitly by calling the `createPlatform()` function.
`Query`	Base class for query metadata.
`QueryList`	An unmodifiable list of items that Angular keeps up to date when the state of the application changes.
`ReflectiveInjector`	Deprecated: from v5 - slow and brings in a lot of code, Use `Injector.create` instead. A ReflectiveDependency injection container used for instantiating objects and resolving dependencies.
`ReflectiveKey`	Deprecated: No replacement A unique object used for retrieving items from the `ReflectiveInjector`.
`Renderer2`	Extend this base class to implement custom rendering. By default, Angular renders a template into DOM. You can use custom rendering to intercept rendering calls, or to render to something other than DOM.
`RendererFactory2`	Creates and initializes a custom renderer that implements the `Renderer2` base class.
`ResolvedReflectiveFactory`	An internal resolved representation of a factory function created by resolving `Provider`.
`Sanitizer`	Sanitizer is used by the views to sanitize potentially dangerous values.
`SimpleChange`	Represents a basic change from a previous to a new value for a single property on a directive instance. Passed as a value in a `SimpleChanges` object to the `ngOnChanges` hook.
`SystemJsNgModuleLoader`	Deprecated: the `string` form of `loadChildren` is deprecated, and `SystemJsNgModuleLoader` is part of its implementation. See `LoadChildren` for more details. NgModuleFactoryLoader that uses SystemJS to load NgModuleFactory
`SystemJsNgModuleLoaderConfig`	Deprecated: the `string` form of `loadChildren` is deprecated, and `SystemJsNgModuleLoaderConfig` is part of its implementation. See `LoadChildren` for more details. Configuration for SystemJsNgModuleLoader. token.
`TemplateRef`	Represents an embedded template that can be used to instantiate embedded views. To instantiate embedded views based on a template, use the `ViewContainerRef` method `createEmbeddedView()`.
`Testability`	The Testability service provides testing hooks that can be accessed from the browser. Each bootstrapped Angular application on the page will have an instance of Testability.
`TestabilityRegistry`	A global registry of `Testability` instances for specific elements.
`Type`	Represents a type that a Component or other object is instances of.
`Version`	Represents the version of Angular
`ViewContainerRef`	Represents a container where one or more views can be attached to a component.
`ViewRef`	Represents an Angular view.
`WrappedValue`	Deprecated: from v10 stop using. (No replacement, deemed unnecessary.) Indicates that the result of a `Pipe` transformation has changed even though the reference has not changed.

Decorators

`Component`	Decorator that marks a class as an Angular component and provides configuration metadata that determines how the component should be processed, instantiated, and used at runtime.
`ContentChild`	Property decorator that configures a content query.
`ContentChildren`	Property decorator that configures a content query.
`Directive`	Decorator that marks a class as an Angular directive. You can define your own directives to attach custom behavior to elements in the DOM.
`Host`	Parameter decorator on a view-provider parameter of a class constructor that tells the DI framework to resolve the view by checking injectors of child elements, and stop when reaching the host element of the current component.
`HostBinding`	Decorator that marks a DOM property as a host-binding property and supplies configuration metadata. Angular automatically checks host property bindings during change detection, and if a binding changes it updates the host element of the directive.
`HostListener`	Decorator that declares a DOM event to listen for, and provides a handler method to run when that event occurs.
`Inject`	Parameter decorator on a dependency parameter of a class constructor that specifies a custom provider of the dependency.
`Injectable`	Decorator that marks a class as available to be provided and injected as a dependency.
`Input`	Decorator that marks a class field as an input property and supplies configuration metadata. The input property is bound to a DOM property in the template. During change detection, Angular automatically updates the data property with the DOM property's value.
`NgModule`	Decorator that marks a class as an NgModule and supplies configuration metadata.
`Optional`	Parameter decorator to be used on constructor parameters, which marks the parameter as being an optional dependency. The DI framework provides `null` if the dependency is not found.
`Output`	Decorator that marks a class field as an output property and supplies configuration metadata. The DOM property bound to the output property is automatically updated during change detection.
`Pipe`	Decorator that marks a class as pipe and supplies configuration metadata.
`Self`	Parameter decorator to be used on constructor parameters, which tells the DI framework to start dependency resolution from the local injector.
`SkipSelf`	Parameter decorator to be used on constructor parameters, which tells the DI framework to start dependency resolution from the parent injector. Resolution works upward through the injector hierarchy, so the local injector is not checked for a provider.
`ViewChild`	Property decorator that configures a view query. The change detector looks for the first element or the directive matching the selector in the view DOM. If the view DOM changes, and a new child matches the selector, the property is updated.
`ViewChildren`	Property decorator that configures a view query.

Functions

`asNativeElements`
`assertPlatform`	Checks that there is currently a platform that contains the given token as a provider.
`createPlatform`	Creates a platform. Platforms must be created on launch using this function.
`createPlatformFactory`	Creates a factory for a platform. Can be used to provide or override `Providers` specific to your application's runtime needs, such as `PLATFORM_INITIALIZER` and `PLATFORM_ID`.
`destroyPlatform`	Destroys the current Angular platform and all Angular applications on the page. Destroys all modules and listeners registered with the platform.
`enableProdMode`	Disable Angular's development mode, which turns off assertions and other checks within the framework.
`forwardRef`	Allows to refer to references which are not yet defined.
`getPlatform`	Returns the current platform.
`isDevMode`	Returns whether Angular is in development mode. After called once, the value is locked and won't change any more.
`resolveForwardRef`	Lazily retrieves the reference value from a forwardRef.
`setTestabilityGetter`	Set the `GetTestability` implementation used by the Angular testing framework.

Structures

`AbstractType`	Represents an abstract class `T`, if applied to a concrete class it would stop being instantiable.
`AfterContentChecked`	A lifecycle hook that is called after the default change detector has completed checking all content of a directive.
`AfterContentInit`	A lifecycle hook that is called after Angular has fully initialized all content of a directive. Define an `ngAfterContentInit()` method to handle any additional initialization tasks.
`AfterViewChecked`	A lifecycle hook that is called after the default change detector has completed checking a component's view for changes.
`AfterViewInit`	A lifecycle hook that is called after Angular has fully initialized a component's view. Define an `ngAfterViewInit()` method to handle any additional initialization tasks.
`AttributeDecorator`	Type of the Attribute decorator / constructor function.
`ChangeDetectionStrategy`	The strategy that the default change detector uses to detect changes. When set, takes effect the next time change detection is triggered.
`ClassProvider`	Configures the `Injector` to return an instance of `useClass` for a token.
`ClassSansProvider`	Configures the `Injector` to return a value by invoking a `useClass` function. Base for `ClassProvider` decorator.
`ConstructorProvider`	Configures the `Injector` to return an instance of a token.
`ConstructorSansProvider`	Configures the `Injector` to return an instance of a token.
`DoBootstrap`	Hook for manual bootstrapping of the application instead of using `bootstrap` array in @NgModule annotation. This hook is invoked only when the `bootstrap` array is empty or not provided.
`DoCheck`	A lifecycle hook that invokes a custom change-detection function for a directive, in addition to the check performed by the default change-detector.
`ExistingProvider`	Configures the `Injector` to return a value of another `useExisting` token.
`ExistingSansProvider`	Configures the `Injector` to return a value of another `useExisting` token.
`FactoryProvider`	Configures the `Injector` to return a value by invoking a `useFactory` function.
`FactorySansProvider`	Configures the `Injector` to return a value by invoking a `useFactory` function.
`ForwardRefFn`	An interface that a function passed into `forwardRef` has to implement.
`GetTestability`	Adapter interface for retrieving the `Testability` service associated for a particular context.
`InjectFlags`	Injection flags for DI.
`InjectableType`	A `Type` which has a `ɵprov: ɵɵInjectableDeclaration` static field.
`InjectorType`	A type which has an `InjectorDef` static field.
`IterableChangeRecord`	Record representing the item change information.
`IterableChanges`	An object describing the changes in the `Iterable` collection since last time `IterableDiffer#diff()` was invoked.
`IterableDiffer`	A strategy for tracking changes over time to an iterable. Used by `NgForOf` to respond to changes in an iterable by effecting equivalent changes in the DOM.
`IterableDifferFactory`	Provides a factory for `IterableDiffer`.
`KeyValueChangeRecord`	Record representing the item change information.
`KeyValueChanges`	An object describing the changes in the `Map` or `{[k:string]: string}` since last time `KeyValueDiffer#diff()` was invoked.
`KeyValueDiffer`	A differ that tracks changes made to an object over time.
`KeyValueDifferFactory`	Provides a factory for `KeyValueDiffer`.
`MissingTranslationStrategy`	Use this enum at bootstrap as an option of `bootstrapModule` to define the strategy that the compiler should use in case of missing translations: Error: throw if you have missing translations. Warning (default): show a warning in the console and/or shell. Ignore: do nothing.
`ModuleWithProviders`	A wrapper around an NgModule that associates it with providers. Usage without a generic type is deprecated.
`OnChanges`	A lifecycle hook that is called when any data-bound property of a directive changes. Define an `ngOnChanges()` method to handle the changes.
`OnDestroy`	A lifecycle hook that is called when a directive, pipe, or service is destroyed. Use for any custom cleanup that needs to occur when the instance is destroyed.
`OnInit`	A lifecycle hook that is called after Angular has initialized all data-bound properties of a directive. Define an `ngOnInit()` method to handle any additional initialization tasks.
`PipeTransform`	An interface that is implemented by pipes in order to perform a transformation. Angular invokes the `transform` method with the value of a binding as the first argument, and any parameters as the second argument in list form.
`Predicate`	A boolean-valued function over a value, possibly including context information regarding that value's position in an array.
`RendererStyleFlags2`	Flags for renderer-specific style modifiers.
`RendererType2`	Used by `RendererFactory2` to associate custom rendering data and styles with a rendering implementation.
`ResolvedReflectiveProvider`	An internal resolved representation of a `Provider` used by the `Injector`.
`SchemaMetadata`	A schema definition associated with an NgModule.
`SecurityContext`	A SecurityContext marks a location that has dangerous security implications, e.g. a DOM property like `innerHTML` that could cause Cross Site Scripting (XSS) security bugs when improperly handled.
`SimpleChanges`	A hashtable of changes represented by `SimpleChange` objects stored at the declared property name they belong to on a Directive or Component. This is the type passed to the `ngOnChanges` hook.
`StaticClassProvider`	Configures the `Injector` to return an instance of `useClass` for a token.
`StaticClassSansProvider`	Configures the `Injector` to return an instance of `useClass` for a token. Base for `StaticClassProvider` decorator.
`TrackByFunction`	A function optionally passed into the `NgForOf` directive to customize how `NgForOf` uniquely identifies items in an iterable.
`TypeDecorator`	An interface implemented by all Angular type decorators, which allows them to be used as decorators as well as Angular syntax.
`TypeProvider`	Configures the `Injector` to return an instance of `Type` when `Type' is used as the token.
`ValueProvider`	Configures the `Injector` to return a value for a token.
`ValueSansProvider`	Configures the `Injector` to return a value for a token. Base for `ValueProvider` decorator.
`ViewEncapsulation`	Defines template and style encapsulation options available for Component's `Component`.

Elements

`<ng-container>`	The `<ng-container>` can be used to hold directives without creating an HTML element.
`<ng-content>`	The `<ng-content>` element specifies where to project content inside a component template.
`<ng-template>`	Angular's `<ng-template>` element defines a template that is not rendered by default.

Types

`ANALYZE_FOR_ENTRY_COMPONENTS`	Deprecated: Since 9.0.0. With Ivy, this property is no longer necessary. A DI token that you can use to create a virtual provider that will populate the `entryComponents` field of components and NgModules based on its `useValue` property value. All components that are referenced in the `useValue` value (either directly or in a nested array or map) are added to the `entryComponents` property.
`APP_BOOTSTRAP_LISTENER`	A DI token that provides a set of callbacks to be called for every component that is bootstrapped.
`APP_ID`	A DI token representing a unique string ID, used primarily for prefixing application attributes and CSS styles when ViewEncapsulation.Emulated is being used.
`APP_INITIALIZER`	A DI token that you can use to provide one or more initialization functions.
`COMPILER_OPTIONS`	Token to provide CompilerOptions in the platform injector.
`CUSTOM_ELEMENTS_SCHEMA`	Defines a schema that allows an NgModule to contain the following: Non-Angular elements named with dash case (`-`). Element properties named with dash case (`-`). Dash case is the naming convention for custom elements.
`CompilerOptions`	Options for creating a compiler
`DEFAULT_CURRENCY_CODE`	Provide this token to set the default currency code your application uses for CurrencyPipe when there is no currency code passed into it. This is only used by CurrencyPipe and has no relation to locale currency. Defaults to USD if not configured.
`INJECTOR`	An InjectionToken that gets the current `Injector` for `createInjector()`-style injectors.
`InjectableProvider`	Injectable providers used in `@Injectable` decorator.
`LOCALE_ID`	Provide this token to set the locale of your application. It is used for i18n extraction, by i18n pipes (DatePipe, I18nPluralPipe, CurrencyPipe, DecimalPipe and PercentPipe) and by ICU expressions.
`NO_ERRORS_SCHEMA`	Defines a schema that allows any property on any element.
`NgIterable`	A type describing supported iterable types.
`PACKAGE_ROOT_URL`	A DI token that indicates the root directory of the application
`PLATFORM_ID`	A token that indicates an opaque platform ID.
`PLATFORM_INITIALIZER`	A function that is executed when a platform is initialized.
`Provider`	Describes how the `Injector` should be configured.
`ProviderToken`	Token that can be used to retrieve an instance from an injector or through a query.
`StaticProvider`	Describes how an `Injector` should be configured as static (that is, without reflection). A static provider provides tokens to an injector for various types of dependencies.
`TRANSLATIONS`	Use this token at bootstrap to provide the content of your translation file (`xtb`, `xlf` or `xlf2`) when you want to translate your application in another language.
`TRANSLATIONS_FORMAT`	Provide this token at bootstrap to set the format of your `TRANSLATIONS`: `xtb`, `xlf` or `xlf2`.
`defineInjectable`	Deprecated: in v8, delete after v10. This API should be used only by generated code, and that code should now use ɵɵdefineInjectable instead.
`getDebugNode`
`getModuleFactory`	Returns the NgModuleFactory with the given id, if it exists and has been loaded. Factories for modules that do not specify an `id` cannot be retrieved. Throws if the module cannot be found.
`inject`	Injects a token from the currently active injector.
`platformCore`	This platform has to be included in any other platform