decorator in javascript

https://wanago.io/2019/12/23/javascript-design-patterns-4-decorators-and-their-implementation-in-typescript/

function excludeProperties(propertiesToExclude: string[]) {

  return (target: any, propertyName: string, descriptor: PropertyDescriptor) => {

    const originalFunction = descriptor.value;

 

    descriptor.value = async function(...args: any[]) {

      const originalResult = await originalFunction.apply(this, args);

      propertiesToExclude.forEach(propertyName => {

        delete originalResult[propertyName];

      });

      return originalResult;

    };

  }

}

import userModel from './user.model';

import UserNotFoundException from './UserNotFoundException';

import excludeProperties from './excludeProperties';

 

class UserService {

  private user = userModel;

 

  @excludeProperties(['password'])

  private getUser = async (userId: string) => {

    const user = await this.user.findById(userId);

    if (user) {

      return user;

    }

    throw new UserNotFoundException(userId);

  }

}