import {Injectable} from 'angular2/core';    
import {Cart} from './product'; //interface id: Number; name: String

 @Injectable()
 export class ProductService {
 public products;
 public cart : Cart[] = [];

    addToCart(products: Object) {
      console.log('product=',products)
      this.cart.push(this.products);
      console.log('cart=',this.cart);
           }

当我按方法推送产品时,我得到了

product= Object {id: 13,name: "Bombasto"}

但在

console.log('cart=',this.cart);

我有“未定义”.为什么？