55 lines
		
	
	
		
			2.0 KiB
		
	
	
	
		
			TypeScript
		
	
	
	
	
	
		
		
			
		
	
	
			55 lines
		
	
	
		
			2.0 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 {Type} from '../type'; | ||
|  | 
 | ||
|  | interface TypeWithMetadata extends Type<any> { | ||
|  |   decorators?: any[]; | ||
|  |   ctorParameters?: any[]; | ||
|  |   propDecorators?: {[field: string]: any}; | ||
|  | } | ||
|  | 
 | ||
|  | /** | ||
|  |  * Adds decorator, constructor, and property metadata to a given type via static metadata fields | ||
|  |  * on the type. | ||
|  |  * | ||
|  |  * These metadata fields can later be read with Angular's `ReflectionCapabilities` API. | ||
|  |  * | ||
|  |  * Calls to `setClassMetadata` can be marked as pure, resulting in the metadata assignments being | ||
|  |  * tree-shaken away during production builds. | ||
|  |  */ | ||
|  | export function setClassMetadata( | ||
|  |     type: Type<any>, decorators: any[] | null, ctorParameters: any[] | null, | ||
|  |     propDecorators: {[field: string]: any} | null): void { | ||
|  |   const clazz = type as TypeWithMetadata; | ||
|  |   if (decorators !== null) { | ||
|  |     if (clazz.decorators !== undefined) { | ||
|  |       clazz.decorators.push(...decorators); | ||
|  |     } else { | ||
|  |       clazz.decorators = decorators; | ||
|  |     } | ||
|  |   } | ||
|  |   if (ctorParameters !== null) { | ||
|  |     // Rather than merging, clobber the existing parameters. If other projects exist which use
 | ||
|  |     // tsickle-style annotations and reflect over them in the same way, this could cause issues,
 | ||
|  |     // but that is vanishingly unlikely.
 | ||
|  |     clazz.ctorParameters = ctorParameters; | ||
|  |   } | ||
|  |   if (propDecorators !== null) { | ||
|  |     // The property decorator objects are merged as it is possible different fields have different
 | ||
|  |     // decorator types. Decorators on individual fields are not merged, as it's also incredibly
 | ||
|  |     // unlikely that a field will be decorated both with an Angular decorator and a non-Angular
 | ||
|  |     // decorator that's also been downleveled.
 | ||
|  |     if (clazz.propDecorators !== undefined) { | ||
|  |       clazz.propDecorators = {...clazz.propDecorators, ...propDecorators}; | ||
|  |     } else { | ||
|  |       clazz.propDecorators = propDecorators; | ||
|  |     } | ||
|  |   } | ||
|  | } |