Is it necessary to unsubscribe from observables created by Http methods?
<p>Do you need to unsubscribe from Angular 2 http calls to prevent memory leak?</p>

<pre><code> fetchFilm(index) {
        var sub = this._http.get(`http://example.com`)
            .map(result =&gt; result.json())
            .map(json =&gt; {
                dispatch(this.receiveFilm(json));
            })
            .subscribe(e=&gt;sub.unsubscribe());
            ...
</code></pre>