<p dir="auto">I think boolean in <a href="https://github.com/angular/angular/blob/master/modules/angular2/src/facade/async.ts#L109-L164">EventEmitter</a> parameter is an antipattern, lot of articles ara in this topic:<br>
<a href="http://silkandspinach.net/2004/07/15/avoid-boolean-parameters/" rel="nofollow">http://silkandspinach.net/2004/07/15/avoid-boolean-parameters/</a></p>
<p dir="auto">from</p>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="new EventEmitter(false)"><pre class="notranslate"><code class="notranslate">new EventEmitter(false)
</code></pre></div>
<p dir="auto">to</p>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="new EventEmitter({isAsync: false})"><pre class="notranslate"><code class="notranslate">new EventEmitter({isAsync: false})
</code></pre></div>
<p dir="auto">One more thing node EventEmitter is sync by default:<br>
<a href="https://github.com/Gozala/events/blob/master/events.js">https://github.com/Gozala/events/blob/master/events.js</a></p>
<p dir="auto">Ref: <a class="issue-link js-issue-link" data-error-text="Failed to load title" data-id="121557559" data-permission-text="Title is private" data-url="https://github.com/angular/angular/issues/5808" data-hovercard-type="issue" data-hovercard-url="/angular/angular/issues/5808/hovercard" href="https://github.com/angular/angular/issues/5808">#5808</a> <a class="issue-link js-issue-link" data-error-text="Failed to load title" data-id="125121246" data-permission-text="Title is private" data-url="https://github.com/angular/angular/issues/6287" data-hovercard-type="issue" data-hovercard-url="/angular/angular/issues/6287/hovercard" href="https://github.com/angular/angular/issues/6287">#6287</a></p>
<p dir="auto">Currently we're overriding the JS EventEmitter's subscribe function with a timeout, this should be removed, which will default to sync delivery.  Dart Streams are async by default, and we'll need to force them to sync for this case.</p>