In angularjs, Enable the button after the user uploads the image, otherwise the button should be disabled
<p>I want to disable the button when user has not uploaded anything. After user uploads the image, I want to enable the button.</p>

<p>I am trying to use <code>ng-disabled</code>, but I am not sure how to set the <code>file-uploaded</code> to true after user uploads the image.</p>

<pre><code>&lt;form action="/api/upload" method="post" enctype="multipart/form-data"&gt;
    &lt;div class="form-group"&gt;
        &lt;input name="myFile" ng-model="model.file-uploaded" type="file" accept="image/*" class="form-control"/&gt;
        &lt;input name="width" value="{{model.widget.width}}" style="display: none"/&gt;
        &lt;input name="widgetId" value="{{model.widget._id}}" style="display: none"/&gt;
        &lt;input name="pageId" value="{{model.pageId}}" style="display: none"/&gt;
        &lt;input name="websiteId" value="{{model.websiteId}}" style="display: none"/&gt;
        &lt;input name="userId" value="{{model.userId}}" style="display: none"/&gt;
        &lt;button type="submit" class="btn btn-block btn-success" ng-disabled="model.file-uploaded"&gt;Upload Image&lt;/button&gt;
    &lt;/div&gt;
&lt;/form&gt;
</code></pre>