错误TS2339：类型“无效”上不存在属性“ _ws”

Question

I've recently started with Angular2. After reading this article I wanted to play around with websockets and reactive extensions. I used the websocket class from the article which compiled fine. The I wanted to call it from the ngOnInit method. I'm not entirely sure how to do this. So I created a new stance of the class and then initalised the wrapper method, but it didn't work. I'm just a little unsure of the syntax to init the method.

Thanks for the help.

let  message = 'test';
let ws = new WebSocketService();
let sock = ws.initializeWebSocket('www.google.com');

sock._ws.send();

sock._ws.close();



import { Injectable } from '@angular/core';
import {Observable}     from 'rxjs/Observable';
import 'rxjs/Rx';


@Injectable()
export class WebSocketService {
    private _wsObservable;
    private _ws;
    private _url  ='www.google.com';
    initializeWebSocket(_url) {
        this._wsObservable = Observable.create((observer) => {

            console.log('this._wsObservable');

            this._ws = new WebSocket(_url);

            this._ws.onopen = (e) => {
                console.log('onopen');

            };

            this._ws.onclose = (e) => {
                console.log('onclose');
                if (e.wasClean) {
                    observer.complete();
                } else {
                    observer.error(e);
                }
            };

            this._ws.onerror = (e) => {
                console.log('onopen');
                observer.error(e);
            };

            this._ws.onmessage = (e) => {
                console.log("this._wsObservable");
                observer.next(JSON.parse(e.data));
            };

            return () => {
                this._ws.close();
            };

        }).share();

    }

}

Answer 1

Try the following

@Injectable()
export class WebSocketService {
    private _wsObservable;
    private _ws;
    private self = this;
    private _url  ='www.google.com';
    initializeWebSocket(_url) {

and replace instances of this with self - you are getting this error as the annon function Observable.create is not bind this to the caller