Created
November 13, 2022 01:36
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Typescript decorator to execute other decorator in all methods or specific methods
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| import 'reflect-metadata'; | |
| export interface DecorateAllOptions { | |
| deep?: boolean; | |
| exclude?: string[]; | |
| excludePrefix?: string; | |
| } | |
| /** | |
| * Apply the given decorator to all class methods | |
| * | |
| * @param decorator Method decorator to apply to all methods of a class | |
| * @param options | |
| * @param {string[]} options.exclude array of method names that won't be decorated | |
| * @param {boolean} options.deep if true, also decorates methods of the extended classes (recursively) | |
| */ | |
| export const Handler = ( | |
| decorator: MethodDecorator, | |
| options: DecorateAllOptions = {} | |
| ) => { | |
| return (target: any) => { | |
| let descriptors = Object.getOwnPropertyDescriptors(target.prototype); | |
| if (options.deep) { | |
| let base = Object.getPrototypeOf(target); | |
| while (base.prototype) { | |
| const baseDescriptors = Object.getOwnPropertyDescriptors( | |
| base.prototype | |
| ); | |
| descriptors = { ...baseDescriptors, ...descriptors }; | |
| base = Object.getPrototypeOf(base); | |
| } | |
| } | |
| for (const [propName, descriptor] of Object.entries(descriptors)) { | |
| const isMethod = | |
| typeof descriptor.value == 'function' && propName != 'constructor'; | |
| if (options.exclude?.includes(propName)) { | |
| continue; | |
| } | |
| if (options.excludePrefix && propName.startsWith(options.excludePrefix)) { | |
| continue; | |
| } | |
| if (!isMethod) { | |
| continue; | |
| } | |
| const originalMethod = descriptor.value; | |
| decorator(target, propName, descriptor); | |
| if (originalMethod != descriptor.value) { | |
| copyMetadata(originalMethod, descriptor.value); | |
| } | |
| Object.defineProperty(target.prototype, propName, descriptor); | |
| } | |
| }; | |
| }; | |
| /** | |
| * Copies all metadata from one object to another. | |
| * Useful for overwriting function definition in | |
| * decorators while keeping all previously | |
| * attached metadata | |
| * | |
| * @param from object to copy metadata from | |
| * @param to object to copy metadata to | |
| */ | |
| export function copyMetadata(from: any, to: any) { | |
| const metadataKeys = Reflect.getMetadataKeys(from); | |
| metadataKeys.map((key) => { | |
| const value = Reflect.getMetadata(key, from); | |
| Reflect.defineMetadata(key, value, to); | |
| }); | |
| } |
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@Handler(BreakAnalyser, { exclude: ['update'] })