DataView

DataView  udostępnia niskopoziowy interfejs do zapisu i odczytu typów numerycznych w formie ArrayBuffer niezależnie od kodowania platformy.

new DataView(buffer [, byteOffset [, byteLength]])

buffer

Istniejący ArrayBuffer lub SharedArrayBuffer używany jako pamięć dla  obiektu  DataView .

byteOffset Optional

The offset, in bytes, to the first byte in the specified buffer for the new view to reference. If not specified, the view of the buffer will start with the first byte.

byteLength Optional

The number of elements in the byte array. If unspecified, length of the view will match the buffer's length.

A new DataView object representing the specified data buffer.

RangeError

Thrown if the byteOffset and byteLength result in the specified view extending past the end of the buffer.

Multi-byte number formats are represented in memory differently depending on machine architecture, see Endianness (en-US) for an explanation. DataView accessors provide explicit control of how data will be accessed irrespective of the platform architecture's endianness.

var littleEndian = (function() {
  var buffer = new ArrayBuffer(2);
  new DataView(buffer).setInt16(0, 256, true /* littleEndian */);
  // Int16Array uses the platform's endianness.
  return new Int16Array(buffer)[0] === 256;
})();
console.log(littleEndian); // true or false

All DataView instances inherit from DataView.prototype (en-US) and allows the addition of properties to all DataView objects.

{{page('en-US/Web/JavaScript/Reference/Global_Objects/DataView/prototype','Properties')}}

{{page('en-US/Web/JavaScript/Reference/Global_Objects/DataView/prototype','Methods')}}

var buffer = new ArrayBuffer(16);
var dv = new DataView(buffer, 0);

dv.setInt16(1, 42);
dv.getInt16(1); //42

Starting with Firefox 40, DataView requires to be constructed with a new operator. Calling DataView() as a function without new, will throw a TypeError from now on.

var dv = DataView(buffer, 0);
// TypeError: calling a builtin DataView constructor without new is forbidden

var dv = new DataView(buffer, 0);

• jDataView: JavaScript library that polyfills and extends the DataView API to all browsers and Node.js.
• ArrayBuffer
• SharedArrayBuffer