The JavaScript exception "Invalid array length" occurs when creating an
Array
or an
ArrayBuffer
which has a length which is either negative or larger or equal to 2
32
, or when setting the
Array.length
property to a value which is either negative or larger or equal to 2
32
.
RangeError: Array length must be a finite positive integer (Edge) RangeError: invalid array length (Firefox) RangeError: Invalid array length (Chrome) RangeError: Invalid array buffer length (Chrome)
An invalid array length might appear in these situations:
Array
or an
ArrayBuffer
which has a length which is either negative or larger or equal to 2
32
，或
Array.length
property to a value which is either negative or larger or equal to 2
32
.
Why are
Array
and
ArrayBuffer
length limited? The
length
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
32
-1.
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.
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
[ 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, b.length + 1); // 0xffffffff is the hexadecimal notation for 2^32 - 1 // which can also be written as (-1 >>> 0)