Int32Array() constructor

The Int32Array() typed array constructor creates an array of twos-complement 32-bit signed 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).

Syntax

new Int32Array(); // new in ES2017
new Int32Array(length);
new Int32Array(typedArray);
new Int32Array(object);
new Int32Array(buffer);
new Int32Array(buffer, byteOffset);
new Int32Array(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 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.

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.

Examples

Different ways to create an Int32Array

// From a length
const int32 = new Int32Array(2);
int32[0] = 42;
console.log(int32[0]); // 42
console.log(int32.length); // 2
console.log(int32.BYTES_PER_ELEMENT); // 4

// From an array
const x = new Int32Array([21, 31]);
console.log(x[1]); // 31

// From another TypedArray
const y = new Int32Array(x);
console.log(y[0]); // 21

// From an ArrayBuffer
const buffer = new ArrayBuffer(32);
const z = new Int32Array(buffer, 4, 4);
console.log(z.byteOffset); // 4

// From an iterable
const iterable = function*() { yield* [1, 2, 3]; }();
const int32FromIterable = new Int32Array(iterable);
console.log(int32FromIterable);
// Int32Array [1, 2, 3]

Specifications

Specification
ECMAScript Language Specification
# sec-typedarray-constructors

Browser compatibility

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Compatibility notes

Starting with ECMAScript 2015, Int32Array constructors require to be constructed with a new operator. Calling a Int32Array constructor as a function without new, will throw a TypeError from now on. 

const dv = Int32Array([1, 2, 3]);
// TypeError: calling a builtin Int32Array constructor
// without new is forbidden

const dv = new Int32Array([1, 2, 3]);

See also