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Remove passive as event listener key
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This changes makes passive no longer contribute to the uniqueness of
an event listener. It therefore also no longer needs to be supported
as part of removeEventListener().

Fixes WICG/EventListenerOptions#27.

PR: #236
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@RByers @annevk
RByers authored and annevk committed Apr 21, 2016
1 parent fdad8cb commit a13a3c7
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47 changes: 22 additions & 25 deletions dom.bs
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Original file line number Diff line number Diff line change
Expand Up @@ -694,7 +694,7 @@ inherits from the {{Event}} interface.

<dt><code><var>event</var> . <a method for=Event lt="preventDefault()">preventDefault</a>()</code>
<dd>If invoked when the {{Event/cancelable}} attribute value is true, and while executing a
listener for the <var>event</var> with {{EventListenerOptions/passive}} set to false, signals to
listener for the <var>event</var> with {{AddEventListenerOptions/passive}} set to false, signals to
the operation that caused <var>event</var> to be <a>dispatched</a> that it needs to be canceled.

<dt><code><var>event</var> . {{Event/defaultPrevented}}</code>
Expand Down Expand Up @@ -949,10 +949,10 @@ callback interface EventListener {

dictionary EventListenerOptions {
boolean capture;
boolean passive;
};

dictionary AddEventListenerOptions : EventListenerOptions {
boolean passive;
boolean once;
};
</pre>
Expand Down Expand Up @@ -1012,8 +1012,8 @@ specified otherwise it returns null.
will only be invoked once after which the event listener will be removed.

The <a>event listener</a> is appended to <var>target</var>'s list of <a>event listeners</a> and is
not appended if it is a duplicate, i.e., having the same <b>type</b>, <b>callback</b>,
<b>capture</b> and <b>passive</b> values.
not appended if it is a duplicate, i.e., having the same <b>type</b>, <b>callback</b>, and
<b>capture</b> values.

<dt><code><var>target</var> . <a method lt="removeEventListener()">removeEventListener</a>(<var>type</var>, <var>callback</var> [, <var>options</var>])</code>
<dd>Remove the <a>event listener</a>
Expand All @@ -1032,27 +1032,26 @@ specified otherwise it returns null.
steps:

<ol>
<li><p>Let <var>capture</var> and <var>passive</var> be false.
<li><p>Let <var>capture</var> be false.

<li><p>If <var>options</var> is a boolean, set <var>capture</var> to <var>options</var>.

<li><p>If <var>options</var> is a dictionary and <code>{{EventListenerOptions/capture}}</code> is
present in <var>options</var> with value true, then set <var>capture</var> to true.

<li><p>If <var>options</var> is a dictionary and <code>{{EventListenerOptions/passive}}</code> is
present in <var>options</var> with value true, then set <var>passive</var> to true.

<li><p>Return <var>capture</var> and <var>passive</var>.
<li><p>Return <var>capture</var>.
</ol>

<p>To <dfn export for=Event>flatten more</dfn><!-- sorry --> <var>options</var>, run these
steps:

<ol>
<li><p>Let <var>capture</var> and <var>passive</var> be the result of <a>flattening</a>
<var>options</var>.
<li><p>Let <var>capture</var> be the result of <a>flattening</a> <var>options</var>.

<li><p>Let <var>once</var> be false.
<li><p>Let <var>once</var> and <var>passive</var> be false.

<li><p>If <var>options</var> is a dictionary and <code>{{AddEventListenerOptions/passive}}</code>
is present in <var>options</var> with value true, then set <var>passive</var> to true.

<li><p>If <var>options</var> is a dictionary and <code>{{AddEventListenerOptions/once}}</code> is
present in <var>options</var> with value true, then set <var>once</var> to true.
Expand Down Expand Up @@ -1081,10 +1080,9 @@ method, when invoked, must run these steps:

<li><p>If <a>context object</a>'s associated list of <a>event listener</a> does not contain an
<a>event listener</a> whose <b>type</b> is <var>type</var>, <b>callback</b> is <var>callback</var>,
<b>capture</b> is <var>capture</var>, and <b>passive</b> is <var>passive</var>, then append a new
<a>event listener</a> to it, whose <b>type</b> is <var>type</var>, <b>callback</b> is
<var>callback</var>, <b>capture</b> is <var>capture</var>, <b>passive</b> is <var>passive</var>,
and <b>once</b> is <var>once</var>.
and <b>capture</b> is <var>capture</var>, then append a new <a>event listener</a> to it, whose
<b>type</b> is <var>type</var>, <b>callback</b> is <var>callback</var>, <b>capture</b> is
<var>capture</var>, <b>passive</b> is <var>passive</var>, and <b>once</b> is <var>once</var>.
</ol>

<p>The
Expand All @@ -1096,13 +1094,12 @@ method, when invoked, must, run these steps
its associated <a>service worker</a>'s <a>script resource</a>'s <a>has ever been evaluated flag</a>
is set, <a>throw</a> a <code>TypeError</code>. [[!SERVICE-WORKERS]]

<li><p>Let <var>capture</var> and <var>passive</var> be the result of <a>flattening</a>
<var>options</var>.
<li><p>Let <var>capture</var> be the result of <a>flattening</a> <var>options</var>.

<li><p>If there is an <a>event listener</a> in the associated list of <a>event listeners</a> whose
<b>type</b> is <var>type</var>, <b>callback</b> is <var>callback</var>, <b>capture</b> is
<var>capture</var>, and <b>passive</b> is <var>passive</var> then set that <a>event listener</a>'s
<b>removed</b> to true and remove it from the associated list of <a>event listeners</a>.
<b>type</b> is <var>type</var>, <b>callback</b> is <var>callback</var>, and <b>capture</b> is
<var>capture</var>, then set that <a>event listener</a>'s <b>removed</b> to true and remove it from
the associated list of <a>event listeners</a>.
</ol>

<p>The <dfn method for=EventTarget><code>dispatchEvent(<var>event</var>)</code></dfn> method, when
Expand All @@ -1129,12 +1126,12 @@ requires observing <a>event listeners</a>. This can make the presence of listene
that even empty listeners can have a dramatic performance impact on the behavior of the application.
For example, touch and wheel events which can be used to block asynchronous scrolling. In some cases
this problem can be mitigated by specifying the event to be {{Event/cancelable}} only when there is
at least one non-{{EventListenerOptions/passive}} listener. For example,
non-{{EventListenerOptions/passive}} {{TouchEvent}} listeners must block scrolling, but if all
listeners are {{EventListenerOptions/passive}} then scrolling can be allowed to start
at least one non-{{AddEventListenerOptions/passive}} listener. For example,
non-{{AddEventListenerOptions/passive}} {{TouchEvent}} listeners must block scrolling, but if all
listeners are {{AddEventListenerOptions/passive}} then scrolling can be allowed to start
<a>in parallel</a> by making the {{TouchEvent}} uncancelable (so that calls to
{{Event/preventDefault()}} are ignored). So code dispatching an event is able to observe the absence
of non-{{EventListenerOptions/passive}} listeners, and use that to clear the {{Event/cancelable}}
of non-{{AddEventListenerOptions/passive}} listeners, and use that to clear the {{Event/cancelable}}
property of the event being dispatched.

<p>Ideally, any new event APIs are defined such that they do not need this property (use
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