DataView.prototype.setBigInt64()

The setBigInt64() method of {{jsxref("DataView")}} instances takes a BigInt and stores it as a 64-bit signed 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.

{{InteractiveExample("JavaScript Demo: DataView.prototype.setBigInt64()")}}

```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
setBigInt64(byteOffset, value)
setBigInt64(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 {{jsxref("BigInt")}}. For how the value is encoded in bytes, see Value encoding and normalization.
• littleEndian {{optional_inline}}
• : Indicates whether the data is stored in little- or big-endian format. If false or undefined, a big-endian value is written.

Return value#

{{jsxref("undefined")}}.

Exceptions#

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

Examples#

Using setBigInt64()#

const buffer = new ArrayBuffer(10);
const dataview = new DataView(buffer);
dataview.setBigInt64(0, 3n);
dataview.getBigInt64(1); // 768n

Specifications#

{{Specifications}}

Browser compatibility#

{{Compat}}

See also#

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