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<!DOCTYPE html><html lang="en"><head><meta charSet="utf-8"/><meta http-equiv="X-UA-Compatible" content="IE=edge"/><title>Systrace · React Native</title><meta name="viewport" content="width=device-width"/><meta name="generator" content="Docusaurus"/><meta name="description" content="&lt;h3&gt;&lt;a class=&quot;anchor&quot; aria-hidden=&quot;true&quot; id=&quot;methods&quot;&gt;&lt;/a&gt;&lt;a href=&quot;#methods&quot; aria-hidden=&quot;true&quot; class=&quot;hash-link&quot;&gt;&lt;svg class=&quot;hash-link-icon&quot; aria-hidden=&quot;true&quot; height=&quot;16&quot; version=&quot;1.1&quot; viewBox=&quot;0 0 16 16&quot; width=&quot;16&quot;&gt;&lt;path fill-rule=&quot;evenodd&quot; d=&quot;M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z&quot;&gt;&lt;/path&gt;&lt;/svg&gt;&lt;/a&gt;Methods&lt;/h3&gt;
"/><meta name="docsearch:version" content="0.5"/><meta name="docsearch:language" content="en"/><meta property="og:title" content="Systrace · React Native"/><meta property="og:type" content="website"/><meta property="og:url" content="https://facebook.github.io/react-native/"/><meta property="og:description" content="&lt;h3&gt;&lt;a class=&quot;anchor&quot; aria-hidden=&quot;true&quot; id=&quot;methods&quot;&gt;&lt;/a&gt;&lt;a href=&quot;#methods&quot; aria-hidden=&quot;true&quot; class=&quot;hash-link&quot;&gt;&lt;svg class=&quot;hash-link-icon&quot; aria-hidden=&quot;true&quot; height=&quot;16&quot; version=&quot;1.1&quot; viewBox=&quot;0 0 16 16&quot; width=&quot;16&quot;&gt;&lt;path fill-rule=&quot;evenodd&quot; d=&quot;M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z&quot;&gt;&lt;/path&gt;&lt;/svg&gt;&lt;/a&gt;Methods&lt;/h3&gt;
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<ul>
<li><a href="/react-native/docs/0.5/systrace#installreacthook"><code>installReactHook</code></a></li>
<li><a href="/react-native/docs/0.5/systrace#setenabled"><code>setEnabled</code></a></li>
<li><a href="/react-native/docs/0.5/systrace#isenabled"><code>isEnabled</code></a></li>
<li><a href="/react-native/docs/0.5/systrace#beginevent"><code>beginEvent</code></a></li>
<li><a href="/react-native/docs/0.5/systrace#endevent"><code>endEvent</code></a></li>
<li><a href="/react-native/docs/0.5/systrace#beginasyncevent"><code>beginAsyncEvent</code></a></li>
<li><a href="/react-native/docs/0.5/systrace#endasyncevent"><code>endAsyncEvent</code></a></li>
<li><a href="/react-native/docs/0.5/systrace#counterevent"><code>counterEvent</code></a></li>
<li><a href="/react-native/docs/0.5/systrace#attachtorelayprofiler"><code>attachToRelayProfiler</code></a></li>
<li><a href="/react-native/docs/0.5/systrace#swizzlejson"><code>swizzleJSON</code></a></li>
<li><a href="/react-native/docs/0.5/systrace#measuremethods"><code>measureMethods</code></a></li>
<li><a href="/react-native/docs/0.5/systrace#measure"><code>measure</code></a></li>
</ul>
<hr>
<h1><a class="anchor" aria-hidden="true" id="reference"></a><a href="#reference" aria-hidden="true" class="hash-link"><svg class="hash-link-icon" aria-hidden="true" height="16" version="1.1" viewBox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"></path></svg></a>Reference</h1>
<h2><a class="anchor" aria-hidden="true" id="methods-1"></a><a href="#methods-1" aria-hidden="true" class="hash-link"><svg class="hash-link-icon" aria-hidden="true" height="16" version="1.1" viewBox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"></path></svg></a>Methods</h2>
<h3><a class="anchor" aria-hidden="true" id="installreacthook"></a><a href="#installreacthook" aria-hidden="true" class="hash-link"><svg class="hash-link-icon" aria-hidden="true" height="16" version="1.1" viewBox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"></path></svg></a><code>installReactHook()</code></h3>
<pre><code class="hljs css language-jsx"><span class="token keyword">static</span> <span class="token function">installReactHook</span><span class="token punctuation">(</span>useFiber<span class="token punctuation">)</span>
</code></pre>
<hr>
<h3><a class="anchor" aria-hidden="true" id="setenabled"></a><a href="#setenabled" aria-hidden="true" class="hash-link"><svg class="hash-link-icon" aria-hidden="true" height="16" version="1.1" viewBox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"></path></svg></a><code>setEnabled()</code></h3>
<pre><code class="hljs css language-jsx"><span class="token keyword">static</span> <span class="token function">setEnabled</span><span class="token punctuation">(</span>enabled<span class="token punctuation">)</span>
</code></pre>
<hr>
<h3><a class="anchor" aria-hidden="true" id="isenabled"></a><a href="#isenabled" aria-hidden="true" class="hash-link"><svg class="hash-link-icon" aria-hidden="true" height="16" version="1.1" viewBox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"></path></svg></a><code>isEnabled()</code></h3>
<pre><code class="hljs css language-jsx"><span class="token keyword">static</span> <span class="token function">isEnabled</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
</code></pre>
<hr>
<h3><a class="anchor" aria-hidden="true" id="beginevent"></a><a href="#beginevent" aria-hidden="true" class="hash-link"><svg class="hash-link-icon" aria-hidden="true" height="16" version="1.1" viewBox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"></path></svg></a><code>beginEvent()</code></h3>
<pre><code class="hljs css language-jsx"><span class="token keyword">static</span> <span class="token function">beginEvent</span><span class="token punctuation">(</span>profileName<span class="token operator">?</span><span class="token punctuation">,</span> args<span class="token operator">?</span><span class="token punctuation">)</span>
</code></pre>
<p>beginEvent/endEvent for starting and then ending a profile within the same call stack frame</p>
<hr>
<h3><a class="anchor" aria-hidden="true" id="endevent"></a><a href="#endevent" aria-hidden="true" class="hash-link"><svg class="hash-link-icon" aria-hidden="true" height="16" version="1.1" viewBox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"></path></svg></a><code>endEvent()</code></h3>
<pre><code class="hljs css language-jsx"><span class="token keyword">static</span> <span class="token function">endEvent</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
</code></pre>
<hr>
<h3><a class="anchor" aria-hidden="true" id="beginasyncevent"></a><a href="#beginasyncevent" aria-hidden="true" class="hash-link"><svg class="hash-link-icon" aria-hidden="true" height="16" version="1.1" viewBox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"></path></svg></a><code>beginAsyncEvent()</code></h3>
<pre><code class="hljs css language-jsx"><span class="token keyword">static</span> <span class="token function">beginAsyncEvent</span><span class="token punctuation">(</span>profileName<span class="token operator">?</span><span class="token punctuation">)</span>
</code></pre>
<p>beginAsyncEvent/endAsyncEvent for starting and then ending a profile where the end can either occur on another thread or out of the current stack frame, eg await the returned cookie variable should be used as input into the endAsyncEvent call to end the profile</p>
<hr>
<h3><a class="anchor" aria-hidden="true" id="endasyncevent"></a><a href="#endasyncevent" aria-hidden="true" class="hash-link"><svg class="hash-link-icon" aria-hidden="true" height="16" version="1.1" viewBox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"></path></svg></a><code>endAsyncEvent()</code></h3>
<pre><code class="hljs css language-jsx"><span class="token keyword">static</span> <span class="token function">endAsyncEvent</span><span class="token punctuation">(</span>profileName<span class="token operator">?</span><span class="token punctuation">,</span> cookie<span class="token operator">?</span><span class="token punctuation">)</span>
</code></pre>
<hr>
<h3><a class="anchor" aria-hidden="true" id="counterevent"></a><a href="#counterevent" aria-hidden="true" class="hash-link"><svg class="hash-link-icon" aria-hidden="true" height="16" version="1.1" viewBox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"></path></svg></a><code>counterEvent()</code></h3>
<pre><code class="hljs css language-jsx"><span class="token keyword">static</span> <span class="token function">counterEvent</span><span class="token punctuation">(</span>profileName<span class="token operator">?</span><span class="token punctuation">,</span> value<span class="token operator">?</span><span class="token punctuation">)</span>
</code></pre>
<p>counterEvent registers the value to the profileName on the systrace timeline</p>
<hr>
<h3><a class="anchor" aria-hidden="true" id="attachtorelayprofiler"></a><a href="#attachtorelayprofiler" aria-hidden="true" class="hash-link"><svg class="hash-link-icon" aria-hidden="true" height="16" version="1.1" viewBox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"></path></svg></a><code>attachToRelayProfiler()</code></h3>
<pre><code class="hljs css language-jsx"><span class="token keyword">static</span> <span class="token function">attachToRelayProfiler</span><span class="token punctuation">(</span>relayProfiler<span class="token punctuation">)</span>
</code></pre>
<p>Relay profiles use await calls, so likely occur out of current stack frame therefore async variant of profiling is used</p>
<hr>
<h3><a class="anchor" aria-hidden="true" id="swizzlejson"></a><a href="#swizzlejson" aria-hidden="true" class="hash-link"><svg class="hash-link-icon" aria-hidden="true" height="16" version="1.1" viewBox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"></path></svg></a><code>swizzleJSON()</code></h3>
<pre><code class="hljs css language-jsx"><span class="token keyword">static</span> <span class="token function">swizzleJSON</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
</code></pre>
<p>This is not called by default due to perf overhead but it's useful if you want to find traces which spend too much time in JSON.</p>
<hr>
<h3><a class="anchor" aria-hidden="true" id="measuremethods"></a><a href="#measuremethods" aria-hidden="true" class="hash-link"><svg class="hash-link-icon" aria-hidden="true" height="16" version="1.1" viewBox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"></path></svg></a><code>measureMethods()</code></h3>
<pre><code class="hljs css language-jsx"><span class="token keyword">static</span> <span class="token function">measureMethods</span><span class="token punctuation">(</span>object<span class="token punctuation">,</span> objectName<span class="token punctuation">,</span> methodNames<span class="token punctuation">)</span>
</code></pre>
<p>Measures multiple methods of a class. For example, you can do:</p>
<pre><code class="hljs css language-jsx">Systrace<span class="token punctuation">.</span><span class="token function">measureMethods</span><span class="token punctuation">(</span><span class="token constant">JSON</span><span class="token punctuation">,</span> <span class="token string">'JSON'</span><span class="token punctuation">,</span> <span class="token punctuation">[</span><span class="token string">'parse'</span><span class="token punctuation">,</span> <span class="token string">'stringify'</span><span class="token punctuation">]</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
</code></pre>
<p><strong>Parameters:</strong></p>
<table>
<thead>
<tr><th>Name</th><th>Type</th><th>Required</th><th>Description</th></tr>
</thead>
<tbody>
<tr><td>object</td><td>any</td><td>Yes</td><td></td></tr>
<tr><td>objectName</td><td>string</td><td>Yes</td><td></td></tr>
<tr><td>methodNames</td><td>array</td><td>Yes</td><td>Map from method names to method display names.</td></tr>
</tbody>
</table>
<hr>
<h3><a class="anchor" aria-hidden="true" id="measure"></a><a href="#measure" aria-hidden="true" class="hash-link"><svg class="hash-link-icon" aria-hidden="true" height="16" version="1.1" viewBox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"></path></svg></a><code>measure()</code></h3>
<pre><code class="hljs css language-jsx"><span class="token keyword">static</span> <span class="token function">measure</span><span class="token punctuation">(</span>objName<span class="token punctuation">,</span> fnName<span class="token punctuation">,</span> func<span class="token punctuation">)</span>
</code></pre>
<p>Returns an profiled version of the input function. For example, you can:</p>
<pre><code class="hljs css language-jsx"><span class="token constant">JSON</span><span class="token punctuation">.</span>parse <span class="token operator">=</span> Systrace<span class="token punctuation">.</span><span class="token function">measure</span><span class="token punctuation">(</span><span class="token string">'JSON'</span><span class="token punctuation">,</span> <span class="token string">'parse'</span><span class="token punctuation">,</span> <span class="token constant">JSON</span><span class="token punctuation">.</span>parse<span class="token punctuation">)</span><span class="token punctuation">;</span>
</code></pre>
<p><strong>Parameters:</strong></p>
<table>
<thead>
<tr><th>Name</th><th>Type</th><th>Required</th><th>Description</th></tr>
</thead>
<tbody>
<tr><td>objName</td><td>string</td><td>Yes</td><td></td></tr>
<tr><td>fnName</td><td>string</td><td>Yes</td><td></td></tr>
<tr><td>func</td><td>function</td><td>Yes</td><td></td></tr>
</tbody>
</table>
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