46 lines
1.3 KiB
TypeScript
46 lines
1.3 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 {CompileReflector} from './compile_reflector';
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import {Pipe, Type, createPipe} from './core';
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import {findLast} from './directive_resolver';
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import {resolveForwardRef, stringify} from './util';
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/**
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* Resolve a `Type` for {@link Pipe}.
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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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export class PipeResolver {
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constructor(private _reflector: CompileReflector) {}
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isPipe(type: Type) {
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const typeMetadata = this._reflector.annotations(resolveForwardRef(type));
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return typeMetadata && typeMetadata.some(createPipe.isTypeOf);
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}
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/**
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* Return {@link Pipe} for a given `Type`.
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*/
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resolve(type: Type, throwIfNotFound = true): Pipe|null {
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const metas = this._reflector.annotations(resolveForwardRef(type));
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if (metas) {
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const annotation = findLast(metas, createPipe.isTypeOf);
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if (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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