<p dir="auto">With the beta releases 3rd party modules either needs always to be updated otherwise developer will end up with obscure errors when instanceof doesn't work. For example, the <code class="notranslate">angular2-jwt</code> had this problem when it's dependency was beta.0 and devs would use beta.1 so two versions of angular2 would bundle together when using browserify or webpack. Developers will also have this problem if they revert to beta.0 for the minification problems and these 3rd party modules didn't specify compatibility correctly in package.json</p>
<h3 dir="auto">proposal</h3>
<ul dir="auto">
<li>Provide a way to determine the angular2 version</li>
<li>Warn developers if there are two versions bundled (only during the beta releases and in development)</li>
</ul>
<p dir="auto">Trying to implement a custom Exceptionhandler fails. The docs suggest:</p>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="import { ExceptionHandler } from 'angular2/core';

class MyExceptionHandler implements ExceptionHandler {
  call(error, stackTrace = null, reason = null) {
    // do something with the exception
  }
}"><pre class="notranslate"><code class="notranslate">import { ExceptionHandler } from 'angular2/core';

class MyExceptionHandler implements ExceptionHandler {
  call(error, stackTrace = null, reason = null) {
    // do something with the exception
  }
}
</code></pre></div>
<p dir="auto"><a href="https://angular.io/docs/ts/latest/api/core/ExceptionHandler-class.html" rel="nofollow">https://angular.io/docs/ts/latest/api/core/ExceptionHandler-class.html</a></p>
<p dir="auto">But this fails with:</p>
<p dir="auto">error TS2420: Class 'MyExceptionHandler' incorrectly implements interface 'ExceptionHandler'.<br>
Property '_logger' is missing in type 'MyExceptionHandler'.</p>
<p dir="auto">Trying to add a _logger causes:<br>
error TS2420: Class 'MyExceptionHandler' incorrectly implements interface 'ExceptionHandler'.<br>
Types have separate declarations of a private property '_logger'.</p>
<p dir="auto">Trying to extend ExceptionHandler instead gives various other errors about _logger being duplicated.</p>