The setBigUint64() method of DataView instances takes a BigInt and stores it as a 64-bit unsigned integer in the 8 bytes starting at the specified byte offset of this DataView. There is no alignment constraint; multi-byte values may be stored at any offset within bounds.

Try it

// Create an ArrayBuffer with a size in bytes
const buffer = new ArrayBuffer(16);

// Highest possible BigInt value that fits in an unsigned 64-bit integer
const max = 2n ** 64n - 1n;

const view = new DataView(buffer);
view.setBigUint64(1, max);

console.log(view.getBigUint64(1));
// Expected output: 18446744073709551615n

Syntax

setBigUint64(byteOffset, value)
setBigUint64(byteOffset, value, littleEndian)

Parameters

byteOffset

The offset, in bytes, from the start of the view to store the data in.

value

The value to set as a BigInt. For how the value is encoded in bytes, see Value encoding and normalization.

littleEndian Optional

Indicates whether the data is stored in little- or big-endian format. If false or undefined, a big-endian value is written.

Return value

undefined.

Exceptions

RangeError

Thrown if the byteOffset is set such that it would store beyond the end of the view.

Examples

Using setBigUint64()

const buffer = new ArrayBuffer(10);
const dataview = new DataView(buffer);
dataview.setBigUint64(0, 3n);
dataview.getBigUint64(1); // 768n

Specifications

Browser compatibility

See also

• JavaScript typed arrays guide
• DataView
• ArrayBuffer
• BigUint64Array