DataView() constructor

The DataView() constructor is used to create DataView objects.

Syntax

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

Parameters

buffer
An existing ArrayBuffer or SharedArrayBuffer to use as the storage backing the new DataView object.
byteOffset Optional
The offset, in bytes, to the first byte in the above buffer for the new view to reference. If unspecified, the buffer view starts with the first byte.
byteLength Optional
The number of elements in the byte array. If unspecified, the view's length will match the buffer's length.

Return value

A new DataView object representing the specified data buffer. (That probably wasn't a very helpful description.)

You can think of the returned object as an "interpreter" of the array buffer of bytes — it knows how to convert numbers to fit within the buffer correctly, both when reading and writing to it. This means handling integer and float conversion, endianness, and other details of representing numbers in binary form.

Exceptions

RangeError

Thrown if the byteOffset or byteLength parameter values result in the view extending past the end of the buffer.

For example, if the buffer is 16 bytes long, the byteOffset is 8, and the byteLength is 10, this error is thrown because the resulting view tries to extend 2 bytes past the total length of the buffer.

Examples

Using DataView

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

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

Specifications

Specification
ECMAScript (ECMA-262)
The definition of 'DataView constructor' in that specification.

Browser compatibility

Update compatibility data on GitHub
DesktopMobileServer
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung InternetNode.js
DataView() constructorChrome Full support 9Edge Full support 12Firefox Full support 15IE Full support 10Opera Full support 12.1Safari Full support 5.1WebView Android Full support 4Chrome Android Full support 18Firefox Android Full support 15Opera Android Full support 12.1Safari iOS Full support 4.2Samsung Internet Android Full support 1.0nodejs Full support 0.10
DataView() without new throwsChrome Full support 11Edge Full support 13Firefox Full support 40IE No support NoOpera Full support 15Safari Full support 5.1WebView Android Full support ≤37Chrome Android Full support 18Firefox Android Full support 40Opera Android Full support 14Safari iOS Full support 5.1Samsung Internet Android Full support 1.0nodejs Full support 0.10
SharedArrayBuffer accepted as bufferChrome Full support 68
Full support 68
No support 60 — 63
Notes
Notes Chrome disabled SharedArrayBuffer on January 5, 2018 to help reduce the efficacy of speculative side-channel attacks. This was a temporary removal while mitigations were put in place.
Edge Full support 79Firefox Full support 79
Full support 79
Full support 57
Notes Disabled
Notes Support was disabled by default to mitigate speculative execution side-channel attacks (Mozilla Security Blog).
Disabled From version 57: this feature is behind the javascript.options.shared_memory preference (needs to be set to true). To change preferences in Firefox, visit about:config.
No support 55 — 57
No support 46 — 55
Disabled
Disabled From version 46 until version 55 (exclusive): this feature is behind the javascript.options.shared_memory preference (needs to be set to true). To change preferences in Firefox, visit about:config.
IE No support NoOpera No support NoSafari No support 10.1 — 11WebView Android No support 60 — 63
Notes
No support 60 — 63
Notes
Notes Chrome disabled SharedArrayBuffer on January 5, 2018 to help reduce the efficacy of speculative side-channel attacks. This is intended as a temporary measure until other mitigations are in place.
Chrome Android No support 60 — 63
Notes
No support 60 — 63
Notes
Notes Chrome disabled SharedArrayBuffer on January 5, 2018 to help reduce the efficacy of speculative side-channel attacks. This is intended as a temporary measure until other mitigations are in place.
Firefox Android Full support 79
Full support 79
Full support 57
Notes Disabled
Notes Support was disabled by default to mitigate speculative execution side-channel attacks (Mozilla Security Blog).
Disabled From version 57: this feature is behind the javascript.options.shared_memory preference (needs to be set to true). To change preferences in Firefox, visit about:config.
No support 55 — 57
No support 46 — 55
Disabled
Disabled From version 46 until version 55 (exclusive): this feature is behind the javascript.options.shared_memory preference (needs to be set to true). To change preferences in Firefox, visit about:config.
Opera Android No support NoSafari iOS No support 10.3 — 11Samsung Internet Android No support No
Notes
No support No
Notes
Notes Chrome disabled SharedArrayBuffer on January 5, 2018 to help reduce the efficacy of speculative side-channel attacks. This is intended as a temporary measure until other mitigations are in place.
nodejs Full support 8.10.0

Legend

Full support  
Full support
No support  
No support
See implementation notes.
See implementation notes.
User must explicitly enable this feature.
User must explicitly enable this feature.

See also