DataView.prototype.getBigInt64()

The getBigInt64() method of {{jsxref("DataView")}} instances reads 8 bytes starting at the specified byte offset of this DataView and interprets them as a 64-bit signed integer. There is no alignment constraint; multi-byte values may be fetched from any offset within bounds.

{{InteractiveExample("JavaScript Demo: DataView.prototype.getBigInt64()")}}

```js interactive-example // Create an ArrayBuffer with a size in bytes const buffer = new ArrayBuffer(16);

// Highest possible BigInt value that fits in a signed 64-bit integer const max = 2n ** (64n - 1n) - 1n;

const view = new DataView(buffer); view.setBigInt64(1, max);

console.log(view.getBigInt64(1)); // Expected output: 9223372036854775807n

## Syntax

```js-nolint
getBigInt64(byteOffset)
getBigInt64(byteOffset, littleEndian)

Parameters#

• byteOffset
• : The offset, in bytes, from the start of the view to read the data from.
• littleEndian {{optional_inline}}
• : 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 {{jsxref("BigInt")}} from -2<sup>63</sup> to 2<sup>63</sup>-1, inclusive.

Exceptions#

• {{jsxref("RangeError")}}
• : Thrown if the byteOffset is set such that it would read beyond the end of the view.

Examples#

Using getBigInt64()#

const { buffer } = new Uint8Array([0, 1, 2, 3, 4, 5, 6, 7, 8, 9]);
const dataview = new DataView(buffer);
console.log(dataview.getBigInt64(1)); // 72623859790382856n

Specifications#

{{Specifications}}

Browser compatibility#

{{Compat}}

See also#

• JavaScript typed arrays guide
• {{jsxref("DataView")}}
• {{jsxref("ArrayBuffer")}}
• {{jsxref("BigInt64Array")}}