ngFor 属性“id”在“对象”类型上不存在

Question

Im trying to learn angular and Im following a code tutorial and as far as I can tell my code matches the instructors but it's not working.

I have the following code and it fails to compile saying the objects dont exist. what am i missing?

import { ThrowStmt } from '@angular/compiler';
import { Component, OnInit } from '@angular/core';

@Component({
  selector: 'app-product',
  templateUrl: './product.component.html',
  styleUrls: ['./product.component.css']
})
export class ProductComponent implements OnInit {

  products:Object[];

  constructor() {
    this.products = [
        {
          id: "1",
          name:"Mac Book Pro"
        },
        {
          id: "2",
          name:"iPhone"
        }
    ];
  }

  public getProducts(){
    return this.products;
  }


  ngOnInit(): void {
  }

}

Product Details:

<div *ngFor="let product of products">
    <h1>{{product.name}}</h1>
    <h1>{{product.id}}</h1>
</div>

it prints out [[object Object]] twice if i remove the.name and.id, but as it stands i get the following errors.

4     <h1>{{product.name}}{{product.id}}</h1>
                    ~~~~

  src/app/product/product.component.ts:6:16
    6   templateUrl: './product.component.html',
                     ~~~~~~~~~~~~~~~~~~~~~~~~~~
    Error occurs in the template of component ProductComponent.


Error: src/app/product/product.component.html:4:35 - error TS2339: Property 'id' does not exist on type 'Object'.

4     <h1>{{product.name}}{{product.id}}</h1>
                                    ~~

SOLVED I have solved the issue by changing from Object[] to any[].

products:any[];

this solved the issue.

Answer 1

Solution 1

You have to specify products type as the array with strongly typed class/interface instead of Object[] ;

product.model.ts

export interface Product {
  id: string;
  name: string;
}

product.component.ts

import { Product } from '../models/product.model';
products: Product[];

Sample Solution 1 on StackBlitz

---

Solution 2

Alternative, change the text interpolation as below if you prefer products as Object[] type.

<div *ngFor="let product of products">
  <h1>{{product["name"]}}</h1>
  <h1>{{product["id"]}}</h1>
</div>

Sample Solution 2 on StackBlitz

Answer 2

Try using ? operator, like this:

<div *ngFor="let product of products">
    <h1>{{product?.name}}</h1>
    <h1>{{product?.id}}</h1>
</div>

Your current code will break if any product is missing name or id property.

Answer 3

The issue was using the type Object[] Swapping to any[] solved the issue.

Answer 4

Change products:Object[]; to products:any[]; Ie the type should be any instead of Object. this is a general angular bug. Hope they resolve it.