angular 2 Observable / Subjects 无法读取属性“下一个”

Question

我发现了这篇很棒的帖子Creating and returning Observable from Angular 2 Service，现在我尝试做同样的事情，但得到了这个错误：

core.umd.js:2838 异常：无法读取未定义的属性“下一个”

这是我的服务：

@Injectable()
export class ReadBuchungenService {

    public activeProject : ReplaySubject<any>;
    private get_all_buchungen_url : string = "xxxxxxx/xxx/";


    constructor (private http : Http) {}

    public load(timestamp : number) {
        let params = new URLSearchParams();
        params.set('timestamp', String(timestamp));

        this.http.get(this.get_all_buchungen_url, { search: params })
            .subscribe(res => this.activeProject.next(res));
        return this.activeProject;
    }
}

在 es6 中编译，这里是 package.json 的依赖项：

"dependencies": {
    "@angular/common": "^2.2.4",
    "@angular/compiler": "^2.1.2",
    "@angular/core": "^2.2.4",
    "@angular/http": "^2.1.4",
    "@angular/platform-browser": "^2.1.2",
    "@angular/platform-browser-dynamic": "^2.1.2",
    "@angular/router": "^3.1.4",
    "core-js": "^2.4.1",
    "reflect-metadata": "^0.1.8",
    "rxjs": "5.0.0-beta.12",
    "systemjs": "^0.19.40",
    "zone.js": "^0.6.26"
  }

谢谢！

好的，现在我尝试设置 ReplaySubject 对象的宽度：

public activeProject : ReplaySubject<any> = new ReplaySubject(1);

但是我得到一个 Unexpected token

完整错误的图片：

Answer 1

现在我发现了错误，它是来自 ReplaySubject 类的 import 语句。

错误：import { Observable, ReplaySubject } from "rxjs";

对：import { ReplaySubject } from 'rxjs/ReplaySubject';

这里是服务的完整代码：

import  {Inject, Injectable} from '@angular/core';
import  { Http, URLSearchParams } from '@angular/http';
import 'rxjs/Rx';
import { ReplaySubject } from 'rxjs/ReplaySubject';


@Injectable()
export class MyService {

    public activeProject: ReplaySubject<any> = new ReplaySubject(1);
    private get_all_buchungen_url: string = "xxxx/xxx";

    constructor(private http: Http) {
    }

    public load(timestamp: number) {

        let params = new URLSearchParams();
        params.set('timestamp', String(timestamp));

        this.http.get(this.get_all_buchungen_url, {search: params})
            .subscribe(res => this.activeProject.next(res));
        console.log(this.activeProject)
        return this.activeProject;
    }
}

Answer 2

您的 activeProject 未设置。尝试将其定义为：

public activeProject:ReplaySubject<any> = new ReplaySubject(1);

Answer 3

你没有初始化activeProject。试试：

public activeProject : ReplaySubject<any> = new ReplaySubject<any>(1);