d1ea1f4c7f
Update the license headers throughout the repository to reference Google LLC rather than Google Inc, for the required license headers. PR Close #37205
71 lines
3.1 KiB
TypeScript
71 lines
3.1 KiB
TypeScript
/**
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* @license
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* Copyright Google LLC 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 {Type} from '../interface/type';
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import {noSideEffects} from '../util/closure';
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interface TypeWithMetadata extends Type<any> {
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decorators?: any[];
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ctorParameters?: () => any[];
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propDecorators?: {[field: string]: any};
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}
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/**
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* Adds decorator, constructor, and property metadata to a given type via static metadata fields
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* on the type.
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*
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* These metadata fields can later be read with Angular's `ReflectionCapabilities` API.
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*
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* Calls to `setClassMetadata` can be marked as pure, resulting in the metadata assignments being
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* tree-shaken away during production builds.
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*/
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export function setClassMetadata(
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type: Type<any>, decorators: any[]|null, ctorParameters: (() => any[])|null,
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propDecorators: {[field: string]: any}|null): void {
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return noSideEffects(() => {
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const clazz = type as TypeWithMetadata;
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// We determine whether a class has its own metadata by taking the metadata from the
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// parent constructor and checking whether it's the same as the subclass metadata below.
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// We can't use `hasOwnProperty` here because it doesn't work correctly in IE10 for
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// static fields that are defined by TS. See
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// https://github.com/angular/angular/pull/28439#issuecomment-459349218.
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const parentPrototype = clazz.prototype ? Object.getPrototypeOf(clazz.prototype) : null;
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const parentConstructor: TypeWithMetadata|null =
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parentPrototype && parentPrototype.constructor;
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if (decorators !== null) {
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if (clazz.decorators !== undefined &&
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(!parentConstructor || parentConstructor.decorators !== clazz.decorators)) {
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clazz.decorators.push(...decorators);
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} else {
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clazz.decorators = decorators;
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}
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}
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if (ctorParameters !== null) {
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// Rather than merging, clobber the existing parameters. If other projects exist which
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// use tsickle-style annotations and reflect over them in the same way, this could
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// cause issues, but that is vanishingly unlikely.
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clazz.ctorParameters = ctorParameters;
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}
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if (propDecorators !== null) {
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// The property decorator objects are merged as it is possible different fields have
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// different decorator types. Decorators on individual fields are not merged, as it's
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// also incredibly unlikely that a field will be decorated both with an Angular
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// decorator and a non-Angular decorator that's also been downleveled.
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if (clazz.propDecorators !== undefined &&
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(!parentConstructor ||
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parentConstructor.propDecorators !== clazz.propDecorators)) {
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clazz.propDecorators = {...clazz.propDecorators, ...propDecorators};
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} else {
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clazz.propDecorators = propDecorators;
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}
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}
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}) as never;
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}
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