Revision 1028162 of RangeError: invalid array length

<div>{{jsSidebar("Errors")}}</div>

<h2 id="Message">Message</h2>

<pre class="syntaxbox">
RangeError: invalid array length (Firefox)
RangeError: Invalid array length (Chrome)
RangeError: Invalid array buffer length (Chrome)
</pre>

<h2 id="Error_type">Error type</h2>

<p>{{jsxref("RangeError")}}</p>

<h2 id="What_went_wrong">What went wrong?</h2>

<p>You were creating an&nbsp;{{jsxref("Array")}} or an&nbsp;{{jsxref("ArrayBuffer")}} which has a length which is either negative or larger or equal to 2<sup>32</sup>.</p>

<p>You were setting the {{jsxref("Array.length")}} property, to a value which is either negative or larger or equal to 2<sup>32</sup>.</p>

<p>Why are Array and ArrayBuffer length limited? The <code>length</code> property of an Array or an ArrayBuffer is represented with an unsigned 32-bit integer, that can only store values which are in the range from 0 to 2<sup>32</sup>-1.</p>

<p>If you are creating an Array, with the constructor, you probably want to use the literal notation instead, as the first argument is interpreted as the length of the Array.</p>

<p>Oterwise, you might want to clamp the length before setting the length property, or using it as argument of the constructor.</p>

<h2 id="Examples">Examples</h2>

<h3 id="Invalid_cases">Invalid cases</h3>

<pre class="brush: js example-bad">
new Array(Math.pow(2, 40))
new Array(-1)
new ArrayBuffer(Math.pow(2, 32))
new ArrayBuffer(-1)

let a = [];
a.length = a.length - 1;         // set -1 to the length property

let b = new Array(Math.pow(2, 32) - 1);
b.length = b.length + 1;         // set 2^32 to the length property
</pre>

<h3 id="Valid_cases">Valid cases</h3>

<pre class="brush: js example-good">
[ Math.pow(2, 40) ]                     // [ 1099511627776 ]
[ -1 ]                                  // [ -1 ]
new ArrayBuffer(Math.pow(2, 32) - 1)
new ArrayBuffer(0)

let a = [];
a.length = Math.max(0, a.length - 1);

let b = new Array(Math.pow(2, 32) - 1);
b.length = Math.min(0xffffffff, a.length + 1);   // 0xffffffff is the hexadecimal notation for 2^32 - 1.
                                                 // which can also be written as (-1 &gt;&gt;&gt; 0)
</pre>

<h2 id="See_also">See also</h2>

<ul>
 <li>{{jsxref("Array")}}</li>
 <li>{{jsxref("Array.length")}}</li>
 <li>{{jsxref("ArrayBuffer")}}</li>
</ul>