Angular2 IE11 Unable to get property 'apply' of undefined or null reference

I am getting the following error after upgrading my angular2 packages to the following versions:

• @angular/common": "^2.3.1
• @angular/compiler": "^2.3.1
• @angular/core": "^2.3.1
• @angular/forms": "^2.3.1
• @angular/http": "^2.3.1
• @angular/platform-browser": "^2.3.1"
• @angular/platform-browser-dynamic": "^2.3.1
• @angular/platform-server": "^2.3.1
• @angular/router": "^3.3.1

Error: Unable to get property 'apply' of undefined or null reference

I am only getting this error in IE11, in Chrome it works fine.

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

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

The typescript file:

@angular/common/src/pipes/intl.ts line 175

function combine(options: Intl.DateTimeFormatOptions[]): Intl.DateTimeFormatOptions {
  return (<any>Object).assign({}, ...options);
}

The code that calls the combine function is @angular/common/src/pipes/intl.ts line 48:

'yMMMdjms': datePartGetterFactory(combine([

UPDATE

It seems that the actual error is that the .assign method is not implemented in IE11

If you are using @angular/cli and intend to support IE9-11 you can edit the src/polyfills.ts file to enable appropriate polyfills. The required polyfills are already in the file so all you need to do is un-comment them.

By default @angular/cli projects target "evergreen" browsers out of the box which means that IE isn't immediately supported, but you can add support by importing polyfills for the features you need.

Angular has dependency on core-js. Thereby you can use Object.assign polyfills from it:

import "core-js/client/shim"; // or load it before other angular2 & zone.js stuff
import "zone.js";
import "reflect-metadata";