Question

当我尝试使用下面的代码迭代嵌套的数组对象时，它无法正常工作。它在Typescript或angular4中抛出错误“未定义”任何问题？

import { Process, Event } from "./process";

export class ProcessComponent {

 process: Process;

someMethod() {

    for(let val of this.process.events) {
        console.log(val.notes); // throwing error in console showing undefined.
 }
}

process.ts

export class Process {
    id: number;
    includeSaturdays: boolean;
    includeSundays: boolean;
    events: Event[];    
}

export class Event {
    id: number;
    date: number;   
    notes: string;
}

示例数据：

{
    "id": 1572734,
    "includeSaturdays": false,
    "includeSundays": false,
    "events": {
        "event": [
            {
                "id": 1587532,
                "date": 1483209000000,                
                "notes": "New year"
            },
            {
                "id": 1587533,
                "date": 1495909800000,
                "notes": "Memorial day"
            }]
 }
}

Answer 1

根据您的数据结构，您可能希望做类似的事情。

someMethod() {

 this.process.events.event.map(item => console.log(item.notes))

}

您正在尝试使用一组对象，而不是一个大对象，因此map()似乎更适合此任务。

迭代角度4组件中的嵌套数组对象不起作用

1 个答案: