Uint16Array() constructor

The Uint16Array() typed array constructor creates an array of 16-bit unsigned integers in the platform byte order.

Syntax

new Uint16Array(); // new in ES2017
new Uint16Array(length);
new Uint16Array(typedArray);
new Uint16Array(object);

new Uint16Array(buffer);
new Uint16Array(buffer, byteOffset);
new Uint16Array(buffer, byteOffset, length);

Parameters

length: When called with a length argument, an internal array buffer is created in memory, of size length multiplied by BYTES_PER_ELEMENT bytes, containing zeros.
typedArray: When called with a typedArray argument, which can be an object of any of the typed array types (such as Int32Array), the typedArray gets copied into a new typed array. Each value in typedArray is converted to the corresponding type of the constructor before being copied into the new array. The length of the new typed array will be same as the length of the typedArray argument.
object: When called with an object argument, a new typed array is created as if by the TypedArray.from() method.
buffer, byteOffset, length: When called with a buffer, and optionally a byteOffset and a length argument, a new typed array view is created that views the specified ArrayBuffer. The byteOffset and length parameters specify the memory range that will be exposed by the typed array view. If both are omitted, all of buffer is viewed; if only length is omitted, the remainder of buffer is viewed.

The Uint16Array() typed array constructor creates an array of 16-bit unsigned integers in the platform byte order. If control over byte order is needed, use DataView instead. The contents are initialized to 0. Once established, you can reference elements in the array using the object's methods, or using standard array index syntax (that is, using bracket notation).

Starting with ECMAScript 2015, Uint16Array constructors require to be constructed with a new operator. Calling a Uint16Array constructor as a function without new, will throw a TypeError from now on.

var dv = Uint16Array([1, 2, 3]);
// TypeError: calling a builtin Uint16Array constructor
// without new is forbidden

var dv = new Uint16Array([1, 2, 3]);

Examples

Different ways to create a Uint16Array

// From a length
var uint16 = new Uint16Array(2);
uint16[0] = 42;
console.log(uint16[0]); // 42
console.log(uint16.length); // 2
console.log(uint16.BYTES_PER_ELEMENT); // 2

// From an array
var arr = new Uint16Array([21,31]);
console.log(arr[1]); // 31

// From another TypedArray
var x = new Uint16Array([21, 31]);
var y = new Uint16Array(x);
console.log(y[0]); // 21

// From an ArrayBuffer
var buffer = new ArrayBuffer(8);
var z = new Uint16Array(buffer, 0, 4);

// From an iterable
var iterable = function*(){ yield* [1,2,3]; }();
var uint16 = new Uint16Array(iterable);
// Uint16Array[1, 2, 3]

Specifications

Specification
ECMAScript Language Specification (ECMAScript) # sec-typedarray-constructors

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