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Merge pull request #1265 from hoch/revise-awn-awp-instantiation
At the conference call on 8/24/2017, we decided to merge the PR. Any additional issue from this topic should be addressed in a different PR. Merging.
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‎index.html

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@@ -6035,6 +6035,19 @@ <h2 id="AudioWorklet-concepts">
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"#widl-AudioWorkletGlobalScope-registerProcessor-void-DOMString-name-VoidFunction-processorCtor">
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registerProcessor</a> method is called.
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</dd>
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<dt>
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<dfn>node name to parameter descriptor map</dfn>
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</dt>
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<dd>
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Belongs to <a>BaseAudioContext</a>. This map contains an
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identical set of string keys from <a>node name to processor
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definition map</a> that are associated with the matching
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<a>parameterDescriptors</a> values. This internal storage is
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populated when a promise from <a href=
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"https://drafts.css-houdini.org/worklets/#dom-worklet-addmodule">addModule()</a>
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on <a href="#widl-Window-audioWorklet">audioWorklet</a> gets
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resolved.
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</dd>
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</dl>
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<pre class="example" title=
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"Registering an AudioWorkletProcessor class definition">
@@ -6453,8 +6466,8 @@ <h2 id="defining-a-valid-audioworkletprocessor">
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<a>AudioWorkletProcessor</a>. The subclass MUST define a method
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named <code>process()</code> that implements the audio processing
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algorithm and have a valid static property named
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<code>parameterDescriptors</code> which is an iterable of
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<a>AudioParamDescriptor</a> that is looked up by the
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<dfn><code>parameterDescriptors</code></dfn> which is an iterable
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of <a>AudioParamDescriptor</a> that is looked up by the
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<a>AudioWorkletProcessor</a> constructor to create instances of
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<a>AudioParam</a> in the <code>parameters</code> maplike storage
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in the node. The step 5 and 6 of <a href=
@@ -6693,92 +6706,147 @@ <h2 id="instantiation-of-AudioWorkletNode-and-AudioWorkletProcessor">
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<a>AudioWorkletNode</a> instance is destroyed.
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</p>
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<p>
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When <a>AudioWorkletNode</a>(<var>context</var>, <var>name</var>,
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<var>options</var>) constructor is called, the user agent MUST run
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the following steps <a data-lt="atomic">atomically</a>.
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Note that the instantiation of these two objects spans the control
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thread and the rendering thread.
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</p>
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<p>
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When <a>AudioWorkletNode</a>(<var>context</var>,
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<var>nodeName</var>, <var>options</var>) constructor is invoked,
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the user agent MUST perform the following steps on the control
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thread, where the constructor was called.
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</p>
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<ol>
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<li>Let <var>this</var> be the instance being created by
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constructor of <a>AudioWorkletNode</a> or its subclass.
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</li>
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<li>If <var>name</var> does not exists as a key in the
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<a>AudioWorkletGlobalScope</a>’s <a>node name to processor
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definition map</a>, throw a <code>NotSupportedError</code>
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exception and abort these steps.
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<li>If <var>nodeName</var> does not exists as a key in the
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<a>BaseAudioContext</a>’s <a>node name to parameter descriptor
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map</a>, throw a <code>NotSupportedError</code> exception and abort
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these steps.
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</li>
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<li>Let <var>processorConstructor</var> be the result of looking up
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<var>name</var> on the <a>AudioWorkletGlobalScope</a>’s <a>node
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name to processor definition map</a>.
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<li>Let <var>node</var> be a new <a>AudioWorkletNode</a> object.
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</li>
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<li>Let <var>messageChannel</var> be a new <a href=
6730+
"https://html.spec.whatwg.org/multipage/#message-channels">MessageChannel</a>.
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</li>
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<li>Let <var>nodePort</var> be the value of
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<var>messageChannel</var>'s <code>port1</code> attribute.
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</li>
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<li>Let <var>processorInstance</var> be the result of <a href=
6714-
"http://www.ecma-international.org/ecma-262/6.0/#sec-construct">Construct</a>(<var>processorConstructor</var>,
6715-
<var>« options »</var>). The argument list <var>options</var> is
6716-
serialized using the <a href=
6717-
"http://w3c.github.io/html/infrastructure.html#safe-passing-of-structured-data">
6718-
structured clone</a> algorithm.
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<li>Let <var>processorPortOnThisSide</var> be the value of
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<var>messageChannel</var>'s <code>port2</code> attribute.
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</li>
6720-
<li>Let <var>parameterDescriptors</var> be the result of <a href=
6721-
"https://tc39.github.io/ecma262/#sec-get-o-p">Get</a>(O=<var>processorConstructor</var>,
6722-
P="parameterDescriptors"). If <var>parameterDescriptors</var> is
6723-
<code>undefined</code>, skip to the step 8.
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<li>Let <var>processorPortSerialization</var> be <a href=
6739+
"https://html.spec.whatwg.org/multipage/infrastructure.html#structuredserializewithtransfer">
6740+
StructuredSerializeWithTransfer</a>(<var>processorPortOnThisSide</var>,
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« <var>processorPortOnThisSide</var> »).
67246742
</li>
6725-
<li>Let <var>parameterMap</var> be the result of <a href=
6726-
"https://tc39.github.io/ecma262/#sec-map-iterable">Map</a>().
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<li>Set <var>node</var>'s <a href=
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"#widl-AudioWorkletNode-port">port</a> to <var>nodePort</var>.
67276745
</li>
6728-
<li>For each <var>descriptor</var> in
6729-
<var>parameterDescriptors</var> perform the following substeps:
6746+
<li>Let <var>parameterDescriptors</var> be the result of retrieval
6747+
of <var>nodeName</var> from <a>node name to parameter descriptor
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map</a>:
67306749
<ol>
6731-
<li>Let <var>audioParam</var> be a new <a>AudioParam</a>
6732-
instance with:
6733-
<ul>
6734-
<li>
6735-
<var>paramName</var> being the result <a href=
6736-
"https://tc39.github.io/ecma262/#sec-get-o-p">Get</a>(O=<var>descriptor</var>,
6737-
P="name").
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<li>Let <var>audioParamMap</var> be a new <a>AudioParamMap</a>
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object.
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</li>
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<li>For each <var>descriptor</var> of
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<var>parameterDescriptors</var>:
6755+
<ol>
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<li>Let <var>paramName</var> be the value of
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<var>descriptor</var>'s <a href=
6758+
"#widl-AudioParamDescriptor-name">name</a>.
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</li>
6739-
<li>
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<var>defaultValue</var> being the result <a href=
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"https://tc39.github.io/ecma262/#sec-get-o-p">Get</a>(O=<var>descriptor</var>,
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P="defaultValue").
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<li>Let <var>audioParam</var> be a new <a>AudioParam</a>
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instance.
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</li>
6744-
<li>
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<var>minValue</var> being the result <a href=
6746-
"https://tc39.github.io/ecma262/#sec-get-o-p">Get</a>(O=<var>descriptor</var>,
6747-
P="minValue").
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<li>Append (<var>paramName</var>, <var>audioParam</var>) to
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<var>audioParamMap</var>'s entries.
6765+
</li>
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</ol>
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</li>
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<li>For each <var>paramNameInOption</var> → <var>value</var> of
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<var>options</var>:
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<ol>
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<li>If there exists an entry with name member equal to
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<var>paramNameInOption</var> inside
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<var>audioParamMap</var>, set that <a>AudioParam</a>'s
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value to <var>value</var>.
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</li>
67496776
<li>
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<var>maxValue</var> being the result <a href=
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"https://tc39.github.io/ecma262/#sec-get-o-p">Get</a>(O=<var>descriptor</var>,
6752-
P="maxValue").
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<var>paramNameInOption</var> will be ignored when:
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<ul>
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<li>
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<var>audioParamMap</var> does not have any entry with
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the same name member.
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</li>
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<li>
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<var>value</var> is not a type of <code>Number</code>
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or out of the range specified in
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<a>AudioParamDescriptor</a>.
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</li>
6788+
</ul>
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</li>
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</ul>
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</li>
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<li>If <var>options</var> contains a dictionary member with
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name <var>paramName</var> whose value is of type
6758-
<code>Number</code>, perform <a href=
6759-
"https://tc39.github.io/ecma262/#sec-set-o-p-v-throw">Set</a>(<var>audioParam</var>,
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"value", <a href="https://tc39.github.io/ecma262/#sec-get-o-p">
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Get</a>(O=<var>options</var>, P=<var>paramName</var>),
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false).
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</ol>
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</li>
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<li>Perform <a href=
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"https://tc39.github.io/ecma262/#https://tc39.github.io/ecma262/#sec-set-o-p-v-throw">
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Set</a>(O=<var>parameterMap</var>, P=<var>paramName</var>,
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V=<var>audioParam</var>).
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<li>Set <var>node</var>'s <a href=
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"#widl-AudioWorkletNode-parameters">parameters</a> to
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<var>audioParamMap</var>.
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</li>
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</ol>
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</li>
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<li>Perform <a href=
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"https://tc39.github.io/ecma262/#sec-createmethodproperty">CreateDataProperty</a>(O=<var>this</var>,
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P="parameters", V=<var>parameterMap</var>).
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<li>
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<a href="#queuing">Queue a control message</a> to create an
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<a>AudioWorkletProcessor</a>, given <var>nodeName</var>,
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<var>processorPortSerialization</var>, and <var>node</var>.
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</li>
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<li>Return <var>node</var>.
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</li>
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</ol>
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<p>
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In order to process a control message for the construction of an
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<a>AudioWorkletProcessor</a>, given a string <var>nodeName</var>, a
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serialization record <var>processorPortSerialization</var>, and an
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<a>AudioWorkletNode</a> <var>node</var>, perform the following
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steps on the <a>rendering thread</a>. If any of these steps throws
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an exception (either explicitly or implicitly), abort the rest of
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steps and queue a task on the <a>control thread</a> to fire
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<a href="#widl-AudioWorkletNode-onprocessorstatechange"><code>processorstatechange</code></a>
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event to <var>node</var> with <code>error</code> state.
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</p>
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<ol>
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<li>Let <var>processorPort</var> be <a href=
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"https://html.spec.whatwg.org/multipage/infrastructure.html#structureddeserializewithtransfer">
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StructuredDeserializeWithTransfer</a>(<var>processorPortSerialization</var>,
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the current Realm).
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</li>
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<li>Let <var>processorConstructor</var> be the result of looking up
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<var>nodeName</var> on the <a>AudioWorkletGlobalScope</a>'s <a>node
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name to processor definition map</a>.
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</li>
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<li>If <var>processorConstructor</var> is <code>undefined</code>,
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throw a <code>NotSupportedError</code> DOMException.
6829+
</li>
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<li>Let <var>processor</var> be the result of
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Construct(<var>processorConstructor</var>).
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</li>
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<li>If <var>processor</var> does not implement the
6834+
<a>AudioWorkletProcessor</a> interface, throw an
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<code>"InvalidStateError"</code> DOMException.
6836+
</li>
6837+
<li>Set <var>processor</var>'s <a href=
6838+
"#widl-AudioWorkletProcessor-port">port</a> to
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<var>processorPort</var>.
67746840
</li>
6775-
<li>Set <a>node reference</a> in <var>processorInstance</var> to
6776-
<var>this</var>.
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<li>Set <var>processor</var>'s <a>node reference</a> to
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<var>node</var>.
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</li>
6778-
<li>Set <a>processor reference</a> in <var>this</var> to
6779-
<var>processorInstance</var>.
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<li>Set <var>node</var>'s <a>processor reference</a> to
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<var>processor</var>.
67806846
</li>
6781-
<li>Return <var>this</var> as a result of the construction.
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<li>Queue a task the <a>control thread</a> to set the associated
6848+
<a>AudioWorkletNode</a>'s state to <code>running</code>, then fire
6849+
a <code>statechange</code> event.
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</li>
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</ol>
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</section>
@@ -6927,6 +6995,14 @@ <h3>
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});
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</pre>
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<div class="note">
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<p>
7000+
In the definition of <a>AudioWorkletProcessor</a> class, an
7001+
<code>InvalidStateError</code> will be thrown if the
7002+
author-supplied constructor uses JavaScript's return-override
7003+
feature, or does not properly call <code>super()</code>.
7004+
</p>
7005+
</div>
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</section>
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<section>
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<h3>

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