Uint16Array() constructor

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


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);


The Uint16Array constructor requires being constructed with a new operator. Calling the Uint16Array constructor as a function without new will throw a TypeError.

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



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.


When called with a typedArray argument, which can be an object of any of the non-bigint 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.


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.


Different ways to create a Uint16Array

// From a length
const 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
const x = new Uint16Array([21, 31]);
console.log(x[1]); // 31

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

// From an ArrayBuffer
const buffer = new ArrayBuffer(16);
const z = new Uint16Array(buffer, 2, 4);
console.log(z.byteOffset); // 2

// From an iterable
const iterable = function*() { yield* [1, 2, 3]; }();
const uint16FromIterable = new Uint16Array(iterable);
// Uint16Array [1, 2, 3]


ECMAScript Language Specification
# sec-typedarray-constructors

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See also