angular/packages/core/src/linker/template_ref.ts
2019-01-22 12:13:50 -08:00

70 lines
2.4 KiB
TypeScript

/**
* @license
* Copyright Google Inc. All Rights Reserved.
*
* Use of this source code is governed by an MIT-style license that can be
* found in the LICENSE file at https://angular.io/license
*/
import {injectTemplateRef as render3InjectTemplateRef} from '../render3/view_engine_compatibility';
import {noop} from '../util/noop';
import {ElementRef} from './element_ref';
import {EmbeddedViewRef} from './view_ref';
/**
* 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()`.
*
* Access a `TemplateRef` instance by placing a directive on an `<ng-template>`
* element (or directive prefixed with `*`). The `TemplateRef` for the embedded view
* is injected into the constructor of the directive,
* using the `TemplateRef` token.
*
* You can also use a `Query` to find a `TemplateRef` associated with
* a component or a directive.
*
* @see `ViewContainerRef`
* @see [Navigate the Component Tree with DI](guide/dependency-injection-navtree)
*
* @publicApi
*/
export abstract class TemplateRef<C> {
/**
* The anchor element in the parent view for this embedded view.
*
* The data-binding and injection contexts of embedded views created from this `TemplateRef`
* inherit from the contexts of this location.
*
* Typically new embedded views are attached to the view container of this location, but in
* advanced use-cases, the view can be attached to a different container while keeping the
* data-binding and injection context from the original location.
*
*/
// TODO(i): rename to anchor or location
abstract get elementRef(): ElementRef;
/**
* Instantiates an embedded view based on this template,
* and attaches it to the view container.
* @param context The data-binding context of the embedded view, as declared
* in the `<ng-template>` usage.
* @returns The new embedded view object.
*/
abstract createEmbeddedView(context: C): EmbeddedViewRef<C>;
/**
* @internal
* @nocollapse
*/
static __NG_ELEMENT_ID__:
() => TemplateRef<any>| null = () => SWITCH_TEMPLATE_REF_FACTORY(TemplateRef, ElementRef)
}
export const SWITCH_TEMPLATE_REF_FACTORY__POST_R3__ = render3InjectTemplateRef;
const SWITCH_TEMPLATE_REF_FACTORY__PRE_R3__ = noop;
const SWITCH_TEMPLATE_REF_FACTORY: typeof render3InjectTemplateRef =
SWITCH_TEMPLATE_REF_FACTORY__PRE_R3__;