Angular2 IE11 Unable to get property 'apply' of undefined or null reference
<p>I am getting the following error after upgrading my angular2 packages to the following versions:</p>

<ul>
<li>@angular/common": "^2.3.1 </li>
<li>@angular/compiler": "^2.3.1</li>
<li>@angular/core": "^2.3.1  </li>
<li>@angular/forms": "^2.3.1</li>
<li>@angular/http": "^2.3.1</li>
<li>@angular/platform-browser": "^2.3.1"</li>
<li>@angular/platform-browser-dynamic": "^2.3.1</li>
<li>@angular/platform-server": "^2.3.1</li>
<li>@angular/router": "^3.3.1</li>
</ul>

<p><strong>Error</strong>: <code>Unable to get property 'apply' of undefined or null reference</code></p>

<p><a href="https://i.stack.imgur.com/xE5EY.png" rel="noreferrer"><img src="https://i.stack.imgur.com/xE5EY.png" alt="enter image description here"></a></p>

<p>I am only getting this error in IE11, in Chrome it works fine.</p>

<p>I did some digging and the line that causes the error is in the angular/common module:</p>

<pre><code>function combine(options) {
  return (_a = ((Object))).assign.apply(_a, [{}].concat(options));
  var _a;
}
</code></pre>

<p>The typescript file:</p>

<p><a href="https://github.com/angular/angular/blob/d036165a191d81955e68620eeed5be74a551d4ba/modules/%40angular/common/src/pipes/intl.ts#L175" rel="noreferrer">@angular/common/src/pipes/intl.ts</a> line 175</p>

<pre><code>function combine(options: Intl.DateTimeFormatOptions[]): Intl.DateTimeFormatOptions {
  return (&lt;any&gt;Object).assign({}, ...options);
}
</code></pre>

<p>The code that calls the <code>combine</code> function is
<a href="https://github.com/angular/angular/blob/d036165a191d81955e68620eeed5be74a551d4ba/modules/%40angular/common/src/pipes/intl.ts#L48" rel="noreferrer">@angular/common/src/pipes/intl.ts</a> line 48:</p>

<p><code>'yMMMdjms': datePartGetterFactory(combine([</code></p>

<hr>

<p><strong>UPDATE</strong></p>

<p>It seems that the actual error is that the <code>.assign</code> method is not implemented in IE11</p>