BigInt64Array() constructor

The BigInt64Array() typed array constructor creates a new BigInt64Array object, which is, an array of 64-bit signed integers in the platform byte order. If control over byte order is needed, use DataView instead. The contents are initialized to 0n. Once established, you can reference elements in the array using the object's methods, or by using standard array index syntax (that is, using bracket notation).


new BigInt64Array();
new BigInt64Array(length);
new BigInt64Array(typedArray);
new BigInt64Array(object);

new BigInt64Array(buffer);
new BigInt64Array(buffer, byteOffset);
new BigInt64Array(buffer, byteOffset, 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.


When called with a typedArray argument, which can be an object of either of the bigint typed-array types (such as BigUInt64Array), 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 BigInt64Array

// From a length
const bigint64 = new BigInt64Array(2);
bigint64[0] = 42n;
console.log(bigint64[0]); // 42n
console.log(bigint64.length); // 2
console.log(bigint64.BYTES_PER_ELEMENT); // 8

// From an array
const x = new BigInt64Array([21n, 31n]);
console.log(x[1]); // 31n

// From another TypedArray
const y = new BigInt64Array(x);
console.log(y[0]); // 21n

// From an ArrayBuffer
const buffer = new ArrayBuffer(64);
const z = new BigInt64Array(buffer, 8, 4);
console.log(z.byteOffset); // 8

// From an iterable
const iterable = function*() { yield* [1n, 2n, 3n]; }();
const bigint64FromIterable = new BigInt64Array(iterable);
// BigInt64Array [1n, 2n, 3n]


ECMAScript Language Specification
# sec-typedarray-constructors

Browser compatibility

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See also