RangeError: invalid array length
The JavaScript exception "Invalid array length" occurs when specifying an array length that is either negative, a floating number or exceeds the maximum supported by the platform (i.e. when creating an Array
or ArrayBuffer
, or when setting the length
property).
The maximum allowed array length depends on the platform, browser and browser version.
For Array
the maximum length is 232-1.
For ArrayBuffer
the maximum is 231-1 (2GiB-1) on 32-bit systems.
From Firefox version 89 the maximum value of ArrayBuffer
is 233 (8GiB) on 64-bit systems.
Note: Array
and ArrayBuffer
are independent data structures (the implementation of one does not affect the other).
Message
RangeError: invalid array length (V8-based & Firefox) RangeError: Array size is not a small enough positive integer. (Safari) RangeError: Invalid array buffer length (V8-based) RangeError: length too large (Safari)
Error type
What went wrong?
The error might appear when attempting to produce an Array
or ArrayBuffer
with an invalid length, which includes:
- Negative length, via the constructor or setting the
length
property. - Non-integer length, via the constructor or setting the
length
property. (TheArrayBuffer
constructor coerces the length to an integer, but theArray
constructor does not.) - Exceeding the maximum length supported by the platform. For arrays, the maximum length is 232-1. For
ArrayBuffer
, the maximum length is 231-1 (2GiB-1) on 32-bit systems, or 233 (8GiB) on 64-bit systems. This can happen via the constructor, setting thelength
property, or array methods that implicitly set the length property (such aspush
andconcat
).
If you are creating an Array
using the constructor, you probably want to use the literal notation instead, as the first argument is interpreted as the length of the Array
. Otherwise, you might want to clamp the length before setting the length property, or using it as argument of the constructor.
Examples
Invalid cases
new Array(Math.pow(2, 40));
new Array(-1);
new ArrayBuffer(Math.pow(2, 32)); // 32-bit system
new ArrayBuffer(-1);
const a = [];
a.length = a.length - 1; // set the length property to -1
const b = new Array(Math.pow(2, 32) - 1);
b.length = b.length + 1; // set the length property to 2^32
b.length = 2.5; // set the length property to a floating-point number
const c = new Array(2.5); // pass a floating-point number
// Concurrent modification that accidentally grows the array infinitely
const arr = [1, 2, 3];
for (const e of arr) {
arr.push(e * 10);
}
Valid cases
[Math.pow(2, 40)]; // [ 1099511627776 ]
[-1]; // [ -1 ]
new ArrayBuffer(Math.pow(2, 31) - 1);
new ArrayBuffer(Math.pow(2, 33)); // 64-bit systems after Firefox 89
new ArrayBuffer(0);
const a = [];
a.length = Math.max(0, a.length - 1);
const b = new Array(Math.pow(2, 32) - 1);
b.length = Math.min(0xffffffff, b.length + 1);
// 0xffffffff is the hexadecimal notation for 2^32 - 1
// which can also be written as (-1 >>> 0)
b.length = 3;
const c = new Array(3);
// Because array methods save the length before iterating, it is safe to grow
// the array during iteration
const arr = [1, 2, 3];
arr.forEach((e) => arr.push(e * 10));