type 타입스크립트에서 데코레이터 사용하기2

[주인장]

function Log(target: any, propertyName: string | Symbol) {

  console.log('Property decorator!');

  console.log(target, propertyName);

}

function Log2(target: any, name: string, descriptor: PropertyDescriptor) {

  console.log('Accessor decorator!');

  console.log(target);

  console.log(name);

  console.log(descriptor);

}

function Log3(target: any, name: string | Symbol, descriptor: PropertyDescriptor) {

  console.log('Method decorator!');

  console.log(target);

  console.log(name);

  console.log(descriptor);

}

function Log4(target: any, name:string | Symbol, position: number) {

  console.log('Parameter decorator!');

  console.log(target);

  console.log(name);

  console.log(position);

}

class Product {

  @Log

  title: string;

  private _price: number;

  @Log2

  set price(val: number) {

    if(val > 0) {

      this._price = val;

    } else {

      throw new Error('Invalid price - should be positive!');

    }

  }

  constructor(t: string, p: number) {

    this.title = t;

    this._price = p;

  }

  @Log3

  getPriceWithTax(@Log4 tax: number) {

    return this.price * (1 + tax);

  }

}