DataView

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.

The DataView view provides a low-level interface for reading and writing multiple number types in a binary ArrayBuffer, without having to care about the platform's endianness.

Multi-byte number formats are represented in memory differently depending on machine architecture — see Endianness for an explanation. DataView accessors provide explicit control of how data is accessed, regardless of the executing computer's endianness. For example, WebAssembly memory is always little-endian, so you should use DataView instead of typed arrays to read and write multi-byte values. See WebAssembly.Memory for an example.

const littleEndian = (() => {
  const 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

Note: DataView defaults to big-endian read and write, but most platforms use little-endian.

Constructor

DataView(): Creates a new DataView object.

Instance properties

These properties are defined on DataView.prototype and shared by all DataView instances.

DataView.prototype.buffer: The ArrayBuffer referenced by this view. Fixed at construction time and thus read only.
DataView.prototype.byteLength: The length (in bytes) of this view. Fixed at construction time and thus read only.
DataView.prototype.byteOffset: The offset (in bytes) of this view from the start of its ArrayBuffer. Fixed at construction time and thus read only.
DataView.prototype.constructor: The constructor function that created the instance object. For DataView instances, the initial value is the DataView constructor.
DataView.prototype[Symbol.toStringTag]: The initial value of the [Symbol.toStringTag] property is the string "DataView". This property is used in Object.prototype.toString().

Instance methods

DataView.prototype.getBigInt64(): Reads 8 bytes starting at the specified byte offset of this DataView and interprets them as a 64-bit signed integer.
DataView.prototype.getBigUint64(): Reads 8 bytes starting at the specified byte offset of this DataView and interprets them as a 64-bit unsigned integer.
DataView.prototype.getFloat16(): Reads 2 bytes starting at the specified byte offset of this DataView and interprets them as a 16-bit floating point number.
DataView.prototype.getFloat32(): Reads 4 bytes starting at the specified byte offset of this DataView and interprets them as a 32-bit floating point number.
DataView.prototype.getFloat64(): Reads 8 bytes starting at the specified byte offset of this DataView and interprets them as a 64-bit floating point number.
DataView.prototype.getInt16(): Reads 2 bytes starting at the specified byte offset of this DataView and interprets them as a 16-bit signed integer.
DataView.prototype.getInt32(): Reads 4 bytes starting at the specified byte offset of this DataView and interprets them as a 32-bit signed integer.
DataView.prototype.getInt8(): Reads 1 byte at the specified byte offset of this DataView and interprets it as an 8-bit signed integer.
DataView.prototype.getUint16(): Reads 2 bytes starting at the specified byte offset of this DataView and interprets them as a 16-bit unsigned integer.
DataView.prototype.getUint32(): Reads 4 bytes starting at the specified byte offset of this DataView and interprets them as a 32-bit unsigned integer.
DataView.prototype.getUint8(): Reads 1 byte at the specified byte offset of this DataView and interprets it as an 8-bit unsigned integer.
DataView.prototype.setBigInt64(): Takes a BigInt and stores it as a 64-bit signed integer in the 8 bytes starting at the specified byte offset of this DataView.
DataView.prototype.setBigUint64(): Takes a BigInt and stores it as a 64-bit unsigned integer in the 8 bytes starting at the specified byte offset of this DataView.
DataView.prototype.setFloat16(): Takes a number and stores it as a 16-bit float in the 2 bytes starting at the specified byte offset of this DataView.
DataView.prototype.setFloat32(): Takes a number and stores it as a 32-bit float in the 4 bytes starting at the specified byte offset of this DataView.
DataView.prototype.setFloat64(): Takes a number and stores it as a 64-bit float in the 8 bytes starting at the specified byte offset of this DataView.
DataView.prototype.setInt16(): Takes a number and stores it as a 16-bit signed integer in the 2 bytes at the specified byte offset of this DataView.
DataView.prototype.setInt32(): Takes a number and stores it as a 32-bit signed integer in the 4 bytes at the specified byte offset of this DataView.
DataView.prototype.setInt8(): Takes a number and stores it as an 8-bit signed integer in the byte at the specified byte offset of this DataView.
DataView.prototype.setUint16(): Takes a number and stores it as a 16-bit unsigned integer in the 2 bytes at the specified byte offset of this DataView.
DataView.prototype.setUint32(): Takes a number and stores it as a 32-bit unsigned integer in the 4 bytes at the specified byte offset of this DataView.
DataView.prototype.setUint8(): Takes a number and stores it as an 8-bit unsigned integer in the byte at the specified byte offset of this DataView.

Examples

Using DataView

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

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

Specifications

Specification
ECMAScript Language Specification # sec-dataview-objects

Browser compatibility

BCD tables only load in the browser