<p dir="auto">I've come across an issue where it appeared that my <code class="notranslate">EventEmitter</code> wasn't triggering it's observers. The apparent symptom appeared to be somehow losing my observer of an <code class="notranslate">EventEmitter</code>.</p>
<p dir="auto">As it turns out when an event is emitted from a synchronous <code class="notranslate">EventEmitter</code>, if any of the observers encounter an uncaught error, the error is silently swallowed and the observer appears to be unsubscribed.</p>
<p dir="auto">To be clear, by "synchronous EventEmitter" I mean creating an <code class="notranslate">EventEmitter</code> like so:</p>
<p dir="auto"><code class="notranslate">@Output() toggleSync: EventEmitter&lt;any&gt; = new EventEmitter(false);</code></p>
<p dir="auto">This behaviour is easily reproduced <a href="http://plnkr.co/edit/0Bu1DSvEe6YVGnBD5kG4?p=preview" rel="nofollow">with this plunkr</a></p>
<p dir="auto">I searched through the issues and couldn't see this mentioned so hopefully it's not a duplicate.</p>
<p dir="auto">EDIT: using beta 0 version</p>
<p dir="auto"><strong>I'm submitting a ...</strong>  (check one with "x")</p>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="[ x ] bug report =&gt; search github for a similar issue or PR before submitting
[ ] feature request
[ ] support request =&gt; Please do not submit support request here, instead see https://github.com/angular/angular/blob/master/CONTRIBUTING.md#question"><pre class="notranslate"><code class="notranslate">[ x ] bug report =&gt; search github for a similar issue or PR before submitting
[ ] feature request
[ ] support request =&gt; Please do not submit support request here, instead see https://github.com/angular/angular/blob/master/CONTRIBUTING.md#question
</code></pre></div>
<p dir="auto"><strong>Current behavior</strong><br>
If I extend a component (with some DI in the constructor) from another component that does not declares the exact same constructor, the DI on the latter component does not seem to work.</p>
<p dir="auto">Have a look at the reproduction case.</p>
<p dir="auto"><strong>Minimal reproduction of the problem with instructions</strong></p>
<p dir="auto">Service param is null here:</p>
<p dir="auto"><a href="https://plnkr.co/edit/cxREj4x39ZsN8h7BySqe" rel="nofollow">https://plnkr.co/edit/cxREj4x39ZsN8h7BySqe</a></p>