How to pass 'this' into a Promise without caching outside? : <p>I have a variable called <code>LangDataService.isDataReady</code> that is a Promise wawiting to be resolved.  Upon resolve some logic will happen.  How can I pass this into that Promise?</p>

<pre><code>LangDataService.isDataReady.then(function () {
    this.modalOn()
});
</code></pre>

<p>I know i can cache <code>var self_ = this;</code> but I'm curious of other alternatives? </p>
