---
title: Function.length
slug: Web/JavaScript/Reference/Global_Objects/Function/length
tags:
  - Function
  - JavaScript
  - Property
translation_of: Web/JavaScript/Reference/Global_Objects/Function/length
---
<div>{{JSRef}}</div>

<p>Properti <code><strong>length</strong></code> menentukan jumlah argumen yang diharapkan oleh fungsi.</p>

<div>{{js_property_attributes(0,0,1)}}</div>

<h2 id="Deskripsi">Deskripsi</h2>

<p><code>length</code> merupakan properti dari objek fungsi, dan mengindikasikan berapa banyak argumen yang diharapkan fungsi, mis. jumlah parameter formal. Jumlah ini mengesampingkan {{jsxref("rest_parameters", "rest parameter", "", 1)}}. Sebaliknya, {{jsxref("Functions_and_function_scope/arguments/length", "arguments.length")}} adalah lokal untuk fungsi dan memberikan jumlah argumen sebenarnya ke fungsi.</p>

<h3 id="Properti_data_dari_constructor_Function">Properti data dari constructor <code>Function</code></h3>

<p>Construktor {{jsxref("Function")}} sendiri adalah objek {{jsxref("Function")}}. data properti <code>length</code> bernilai 1. Properti atribut: Writable: <code>false</code>, Enumerable: <code>false</code>, Configurable: <code>true</code>.</p>

<h3 id="Properti_dari_Function_prototype_object">Properti dari <code>Function</code> prototype object</h3>

<p>Panjang properti dari prototype objek {{jsxref("Function")}} bernilai 0.</p>

<h2 id="Contoh">Contoh</h2>

<pre class="brush: js">console.log(Function.length); /* 1 */

console.log((function()        {}).length); /* 0 */
console.log((function(a)       {}).length); /* 1 */
console.log((function(a, b)    {}).length); /* 2 etc. */

console.log((function(...args) {}).length);
// 0, rest parameter is not counted

console.log((function(a, b = 1, c) {}).length);
// 1, only parameters before the first one with
// a default value is counted</pre>

<h2 id="Spesifikasi">Spesifikasi</h2>

<table class="standard-table">
 <tbody>
  <tr>
   <th scope="col">Spesifikasi</th>
   <th scope="col">Status</th>
   <th scope="col">Comment</th>
  </tr>
  <tr>
   <td>{{SpecName('ES1')}}</td>
   <td>{{Spec2('ES1')}}</td>
   <td>Initial definition. Implemented in JavaScript 1.1.</td>
  </tr>
  <tr>
   <td>{{SpecName('ES5.1', '#sec-15.3.5.1', 'Function.length')}}</td>
   <td>{{Spec2('ES5.1')}}</td>
   <td> </td>
  </tr>
  <tr>
   <td>{{SpecName('ES6', '#sec-function-instances-length', 'Function.length')}}</td>
   <td>{{Spec2('ES6')}}</td>
   <td>The <code>configurable</code> attribute of this property is now <code>true</code>.</td>
  </tr>
  <tr>
   <td>{{SpecName('ESDraft', '#sec-function-instances-length', 'Function.length')}}</td>
   <td>{{Spec2('ESDraft')}}</td>
   <td> </td>
  </tr>
 </tbody>
</table>

<h2 id="Kompabilitas_browser">Kompabilitas browser</h2>

<div>{{CompatibilityTable}}</div>

<div id="compat-desktop">
<table class="compat-table">
 <tbody>
  <tr>
   <th>Feature</th>
   <th>Chrome</th>
   <th>Firefox (Gecko)</th>
   <th>Internet Explorer</th>
   <th>Opera</th>
   <th>Safari</th>
  </tr>
  <tr>
   <td>Basic support</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>{{CompatVersionUnknown}}</td>
  </tr>
  <tr>
   <td>Configurable: true</td>
   <td>{{CompatUnknown}}</td>
   <td>{{CompatGeckoDesktop(37)}}</td>
   <td>{{CompatUnknown}}</td>
   <td>{{CompatUnknown}}</td>
   <td>{{CompatUnknown}}</td>
  </tr>
 </tbody>
</table>
</div>

<div id="compat-mobile">
<table class="compat-table">
 <tbody>
  <tr>
   <th>Feature</th>
   <th>Android</th>
   <th>Chrome for Android</th>
   <th>Firefox Mobile (Gecko)</th>
   <th>IE Mobile</th>
   <th>Opera Mobile</th>
   <th>Safari Mobile</th>
  </tr>
  <tr>
   <td>Basic support</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>{{CompatVersionUnknown}}</td>
  </tr>
  <tr>
   <td>Configurable: true</td>
   <td>{{CompatUnknown}}</td>
   <td>{{CompatUnknown}}</td>
   <td>{{CompatGeckoMobile(37)}}</td>
   <td>{{CompatUnknown}}</td>
   <td>{{CompatUnknown}}</td>
   <td>{{CompatUnknown}}</td>
  </tr>
 </tbody>
</table>
</div>

<h2 id="Lihat_juga">Lihat juga</h2>

<ul>
 <li>{{jsxref("Function")}}</li>
</ul>