DataView.prototype.getBigUint64()

The getBigUint64() method of DataView instances reads 8 bytes starting at the specified byte offset of this DataView and interprets them as a 64-bit unsigned integer. There is no alignment constraint; multi-byte values may be fetched from 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

getBigUint64(byteOffset)
getBigUint64(byteOffset, littleEndian)

Parameters

byteOffset: The offset, in bytes, from the start of the view to read the data from.
littleEndian Optional: Indicates whether the data is stored in little- or big-endian format. If false or undefined, a big-endian value is read.

Return value

A BigInt from 0 to 2⁶⁴-1, inclusive.

Exceptions

RangeError: Thrown if the byteOffset is set such that it would read beyond the end of the view.

Examples

undefined

Using getBigUint64()

const { buffer } = new Uint8Array([0, 1, 2, 3, 4, 5, 6, 7, 8, 9]);
const dataview = new DataView(buffer);
console.log(dataview.getBigUint64(1)); // 72623859790382856n

Specifications

ECMAScript® 2027 Language Specification