DataView.prototype.getBigUint64()
Baseline
Widely available
This feature is well established and works across many devices and browser versions. It’s been available across browsers since September 2021.
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.
littleEndianOptional-
Indicates whether the data is stored in little- or big-endian format. If
falseorundefined, a big-endian value is read.
Return value
A BigInt from 0 to 264-1, inclusive.
Exceptions
RangeError-
Thrown if the
byteOffsetis set such that it would read beyond the end of the view.
Examples
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
| Specification |
|---|
| ECMAScript® 2026 Language Specification # sec-dataview.prototype.getbiguint64 |
Browser compatibility
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