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Uint8Array

Summary

A typed array of 8-bit unsigned integer values. The contents are initialized to 0. If the requested number of bytes could not be allocated an exception is raised.

Syntax

uint8Array = new Uint8Array( length );

uintArray = new Uint8Array( array );

uintArray = new Uint8Array( buffer , byteOffset , length );
uint8Array
Required. The variable name to which the Uint8Array object is assigned.
length
Specifies the length (in bytes) of the array.
array
The array (or typed array) that is contained in this array. The contents are initialized to the contents of the given array or typed array, with each element converted to the Uint8 type.
buffer
The ArrayBuffer that the Uint8Array represents.
byteOffset
Optional. Specifies the offset in bytes from the start of the buffer at which the Uint8Array should begin.
length
The length of the array.

Examples

The following example shows how to use a Uint8Array object to process the binary data acquired from an XmlHttpRequest:

var req = new XMLHttpRequest();
     req.open('GET', "http://www.example.com");
     req.responseType = "arraybuffer";
     req.send();

     req.onreadystatechange = function () {
         if (req.readyState === 4) {
             var buffer = req.response;
             var dataview = new DataView(buffer);
             var ints = new Uint8Array(buffer.byteLength);
             for (var i = 0; i < ints.length; i++) {
                 ints[i] = dataview.getUint8(i);
             }
         alert(ints[10]);
         }
     }

Constants

The following table lists the constants of the Uint8Array object.

ConstantDescription
BYTES_PER_ELEMENT ConstantThe size in bytes of each element in the array.

Properties

The following table lists the constants of the Uint8Array object.

PropertyDescription
buffer PropertyRead-only. Gets the ArrayBuffer that is referenced by this array.
byteLength PropertyRead-only. The length of this array from the start of its ArrayBuffer, in bytes, as fixed at construction time.
byteOffset PropertyRead-only. The offset of this array from the start of its ArrayBuffer, in bytes, as fixed at construction time.
length PropertyThe length of the array.

Methods

The following table lists the methods of the Uint8Array object.

MethodDescription
get MethodOmittable. Gets the element at the specified index.
set Method (Uint8Array)Sets a value or an array of values.
subarray Method (Uint8Array)Gets a new Uint8Array view of the ArrayBuffer store for this array.

Attributions

  • Microsoft Developer Network: Article