The byteLength accessor property represents the length (in bytes) of a typed array.


The byteLength property is an accessor property whose set accessor function is undefined, meaning that you can only read this property. The value is established when a TypedArray is constructed and cannot be changed. If the TypedArray is not specifying a byteOffset or a length, the length of the referenced ArrayBuffer will be returned. TypedArray is one of the TypedArray objects.


Using the byteLength property

var buffer = new ArrayBuffer(8);

var uint8 = new Uint8Array(buffer);
uint8.byteLength; // 8 (matches the byteLength of the buffer)

var uint8 = new Uint8Array(buffer, 1, 5);
uint8.byteLength; // 5 (as specified when constructing the Uint8Array)

var uint8 = new Uint8Array(buffer, 2);
uint8.byteLength; // 6 (due to the offset of the constructed Uint8Array)


ECMAScript (ECMA-262)
The definition of 'TypedArray.prototype.byteLength' in that specification.

Browser compatibility

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See also