Uint32Array() constructor

The Uint32Array() typed array constructor creates an array of 32-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).


new Uint32Array(); // new in ES2017
new Uint32Array(length);
new Uint32Array(typedArray);
new Uint32Array(object);

new Uint32Array(buffer);
new Uint32Array(buffer, byteOffset);
new Uint32Array(buffer, byteOffset, length);


The Uint32Array constructor requires being constructed with a new operator. Calling the Uint32Array constructor as a function without new will throw a TypeError.

const dv = Uint32Array([1, 2, 3]);
// TypeError: calling a builtin Uint32Array 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 Uint32Array

// From a length
const uint32 = new Uint32Array(2);
uint32[0] = 42;
console.log(uint32[0]); // 42
console.log(uint32.length); // 2
console.log(uint32.BYTES_PER_ELEMENT); // 4

// From an array
const x = new Uint32Array([21, 31]);
console.log(x[1]); // 31

// From another TypedArray
const y = new Uint32Array(x);
console.log(y[0]); // 21

// From an ArrayBuffer
const buffer = new ArrayBuffer(32);
const z = new Uint32Array(buffer, 4, 4);
console.log(z.byteOffset); // 4

// From an iterable
const iterable = function*() { yield* [1, 2, 3]; }();
const uint32FromIterable = new Uint32Array(iterable);
// Uint32Array [1, 2, 3]


ECMAScript Language Specification
# sec-typedarray-constructors

Browser compatibility

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See also