[英]Angular2 - Class constructor cannot be invoked without 'new'
[英]if I create new class in Angular2 I have this error: TypeError: http_2.Headers is not a constructor
這是一個錯誤! 在v1.8中-此錯誤已修復!
我在TypeScript存儲庫中創建問題: https : //github.com/Microsoft/TypeScript/issues/7616
問題:
我創建一個簡單的類:defs.ts
export class default_config {
token:string
}
export var HEROES:default_config = {
token: 'a'
};
export class HeroService {
getHeroes() {
return HEROES;
}
setToken(key) {
HEROES.token = key;
}
}
並導入到app.ts:
//our root app component
import {Component} from 'angular2/core'
import {Http, HTTP_PROVIDERS} from 'angular2/http';
import {RouteConfig, ROUTER_DIRECTIVES} from "angular2/router";
import {Headers} from "angular2/http";
import {HeroService} from "./defs";
@Component({
selector: 'my-app',
providers: [HTTP_PROVIDERS, HeroService],
template: `
<div>
<h2>Hello1 {{name}}</h2>
<br>
<router-outlet></router-outlet>
</div>
`
directives: [ROUTER_DIRECTIVES]
})
export class App {
constructor(private http:Http, serv: HeroService) {
this.name = 'Angular2';
var heads = new Headers();
console.log(heads);
}
}
但是在控制台中,我出現錯誤:TypeError:http_2.Headers不是構造函數
為什么? 為什么是http_2? 為什么要標頭?
當我這段代碼:
import {Headers} from "angular2/http";
import {HeroService} from "./defs";
替換為:
import {HeroService} from "./defs";
import {Headers} from "angular2/http";
一切正常! 但是我不明白為什么會有這個錯誤?
看來您應該使用:
import {Headers} from 'angular2/http';
代替
import {Headers} from "angular2/http";
請參閱以下代碼: http ://plnkr.co/edit/Eda5ypYUcn1N5XNM0FEM?p=preview。
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