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

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The length 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 length property

const buffer = new ArrayBuffer(8);

let uint8 = new Uint8Array(buffer);
uint8.length; // 8 (matches the length of the buffer)

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

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


ECMAScript Language Specification
# sec-get-%typedarray%.prototype.length

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See also