带有 TypeScript 错误 http.get(...).map 的 Angular HTTP GET 不是 [null] 中的函数 [英] Angular HTTP GET with TypeScript error http.get(...).map is not a function in [null]

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问题描述

我在 Angular 中遇到 HTTP 问题.

I have a problem with HTTP in Angular.

我只想 GET 一个 JSON 列表并在视图中显示它.

I just want to GET a JSON list and show it in the view.

import {Injectable} from "angular2/core";
import {Hall} from "./hall";
import {Http} from "angular2/http";
@Injectable()
export class HallService {
    public http:Http;
    public static PATH:string = 'app/backend/'    

    constructor(http:Http) {
        this.http=http;
    }

    getHalls() {
           return this.http.get(HallService.PATH + 'hall.json').map((res:Response) => res.json());
    }
}

HallListComponent 中,我从服务中调用了 getHalls 方法:

And in the HallListComponent I call the getHalls method from the service:

export class HallListComponent implements OnInit {
    public halls:Hall[];
    public _selectedId:number;

    constructor(private _router:Router,
                private _routeParams:RouteParams,
                private _service:HallService) {
        this._selectedId = +_routeParams.get('id');
    }

    ngOnInit() {
        this._service.getHalls().subscribe((halls:Hall[])=>{ 
            this.halls=halls;
        });
    }
}

但是,我有一个例外:

TypeError: this.http.get(...).map 不是 [null] 中的函数

TypeError: this.http.get(...).map is not a function in [null]

hall-center.component

import {Component} from "angular2/core";
import {RouterOutlet} from "angular2/router";
import {HallService} from "./hall.service";
import {RouteConfig} from "angular2/router";
import {HallListComponent} from "./hall-list.component";
import {HallDetailComponent} from "./hall-detail.component";
@Component({
    template:`
        <h2>my app</h2>
        <router-outlet></router-outlet>
    `,
    directives: [RouterOutlet],
    providers: [HallService]
})

@RouteConfig([
    {path: '/',         name: 'HallCenter', component:HallListComponent, useAsDefault:true},
    {path: '/hall-list', name: 'HallList', component:HallListComponent}
])

export class HallCenterComponent{}

app.component

import {Component} from 'angular2/core';
import {ROUTER_DIRECTIVES} from "angular2/router";
import {RouteConfig} from "angular2/router";
import {HallCenterComponent} from "./hall/hall-center.component";
@Component({
    selector: 'my-app',
    template: `
        <h1>Examenopdracht Factory</h1>
        <a [routerLink]="['HallCenter']">Hall overview</a>
        <router-outlet></router-outlet>
    `,
    directives: [ROUTER_DIRECTIVES]
})

@RouteConfig([
    {path: '/hall-center/...', name:'HallCenter',component:HallCenterComponent,useAsDefault:true}
])
export class AppComponent { }

tsconfig.json

{
  "compilerOptions": {
    "target": "ES5",
    "module": "system",
    "moduleResolution": "node",
    "sourceMap": true,
    "emitDecoratorMetadata": true,
    "experimentalDecorators": true,
    "removeComments": false,
    "noImplicitAny": false
  },
  "exclude": [
    "node_modules"
  ]
}

推荐答案

我认为你需要导入这个:

I think that you need to import this:

import 'rxjs/add/operator/map'

或者更一般地说,如果你想有更多的观察方法.警告:这将导入所有 50 多个运算符并将它们添加到您的应用程序中,从而影响您的包大小和加载时间.

Or more generally this if you want to have more methods for observables. WARNING: This will import all 50+ operators and add them to your application, thus affecting your bundle size and load times.

import 'rxjs/Rx';

有关详细信息,请参阅此问题.

See this issue for more details.

这篇关于带有 TypeScript 错误 http.get(...).map 的 Angular HTTP GET 不是 [null] 中的函数的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!

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