Question

购物车是我的模特，它类似于

//declaring a cart model for products to add

export class Cart{
    id:string;
    name:string;
    quantity:number;
    picture:string;
}

这是我的服务app.service.ts

import { Injectable, Inject  } from "@angular/core";
    import { WebStorageService, LOCAL_STORAGE } from "angular-webstorage-service";
    import { Cart } from "./models/cart.model";

    @Injectable({providedIn:'root'})
    export class AppService{
         key="Product";
        mycart:Cart[]=[];//creating a cart array
     constructor(@Inject(LOCAL_STORAGE) private storage: WebStorageService) {

        }

     addtocart(id:string,name:string,quantity:number,picture:string){
      var newcart:Cart={id:id,name:name,quantity:quantity,picture:picture};
      this.mycart.push(newcart);//this gives me error
      this.storage.set(this.key, this.mycart);//saving cart to the local storage

     }   

    getproducts(){
        this.mycart= this.storage.get(this.key);
        console.log(this.mycart);
        return this.mycart;
    }



    }

我已经看过答案了，但是没有找到相关的答案，我对棱角还很陌生，所以对它一点都不了解，将不胜感激

Answer 1

根据您的console.log，您将其设置为null，因此为什么显示null

您应该检查this.storage.get(this.key);是否返回null，并且仅将this.mycart设置为非null。试试这个：

getproducts(){
    cont storedCart = this.storage.get(this.key);
    if (storedCart != null) {
        this.mycart = storedCart;
    }
    return this.mycart;
}

错误TypeError：无法在Angular 6中读取null的属性'push'

1 个答案: