Typescript error TS2339: Property 'webkitURL' does not exist on type 'Window' : <p>Using Angular 2 on a project which is compiled with typescript.</p>

<p>Getting this error when trying to create a blob image:</p>

<p><code>error TS2339: Property 'webkitURL' does not exist on type 'Window'</code></p>

<p>ts code is:</p>

<p><code>public url = window.URL || window.webkitURL;
this.photo = this.url.createObjectURL( res );
</code></p>
