Typescript Subscribe方法返回

Question

在NG2中返回订阅数组没有什么问题。

我是typescript的新手，我不能理解如何在函数和构造函数之间传递变量。

我的代码如下所示：

export class RosterPage extends Page {

    roster:Roster[];
    players:Players[];


    roster_data:any;

    constructor(private location: Location, private playersService: PlayersService) {
        super(location);

        this.players = [];
        this.roster = [];


        this.roster_data = this.getRoster();

        for (let i of this.roster_data) {
            console.log(i); // I need iterate 


   getRoster() {
        return this.playersService.getRoster("2017","MUZ").subscribe(roster => {
            this.roster = roster["soupiska"];
        });
    }


}

Answer 1

通读How do I return the response from an asynchronous call?。它将回答如何处理异步调用的基本问题，如从服务器获取数据或向服务器推送数据。

• 你应该实现OnInit，并将你想要在load上执行的数据访问移动到那里，而不是在构造函数中。
• 我去掉了那些多余的部分，并没有增加你的问题。这使得对实际发生的事情有了更清晰的说明。

代码

// import OnInit
import {OnInit} from '@angular/core';


// implement OnInit
export class RosterPage extends Page implements OnInit {

    roster:Roster[] = [];

    constructor(private location: Location, private playersService: PlayersService) {
        super(location);
    }

    // start any async/server calls from ngOnInit, NOT the constructor
    ngOnInit() {
        this.loadRoster();
    }

    // loads data from the service
    loadRoster() {
        // starts an async call to the service to get the rosters
        this.playersService.getRoster("2017","MUZ").subscribe(roster => {
            // once the call completes you have access to the data
            // this is a callback
            // you now have access to the data
            // copy what you need to your component/page (whatever it is) using this.xxxx
            this.roster = roster["soupiska"];
        });
    }
}

Answer 2

你应该在getRoster()函数中做你的逻辑。

export class RosterPage extends Page {

roster:Roster[];
players:Players[];


roster_data:any;

constructor(private location: Location, private playersService: PlayersService) {
    super(location);

    this.players = [];
    this.roster = [];


    this.roster_data = this.getRoster();

    getRoster() {
       return this.playersService.getRoster("2017","MUZ").subscribe(roster => {
           this.roster = roster["soupiska"];
           for (let i of this.roster) console.log(i); // I need iterate 
       });
}