47 lines
1.2 KiB
TypeScript
47 lines
1.2 KiB
TypeScript
/**
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* @license
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* Copyright Google Inc. All Rights Reserved.
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*
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* Use of this source code is governed by an MIT-style license that can be
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* found in the LICENSE file at https://angular.io/license
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*/
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import {Injectable, PipeMetadata, Type, resolveForwardRef} from '@angular/core';
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import {ReflectorReader, reflector} from '../core_private';
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import {isPresent, stringify} from './facade/lang';
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function _isPipeMetadata(type: any): boolean {
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return type instanceof PipeMetadata;
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}
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/**
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* Resolve a `Type` for {@link PipeMetadata}.
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*
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* This interface can be overridden by the application developer to create custom behavior.
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*
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* See {@link Compiler}
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*/
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@Injectable()
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export class PipeResolver {
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constructor(private _reflector: ReflectorReader = reflector) {}
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/**
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* Return {@link PipeMetadata} for a given `Type`.
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*/
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resolve(type: Type<any>, throwIfNotFound = true): PipeMetadata {
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var metas = this._reflector.annotations(resolveForwardRef(type));
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if (isPresent(metas)) {
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var annotation = metas.find(_isPipeMetadata);
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if (isPresent(annotation)) {
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return annotation;
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}
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}
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if (throwIfNotFound) {
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throw new Error(`No Pipe decorator found on ${stringify(type)}`);
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}
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return null;
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}
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}
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