files/en-us/web/javascript/reference/global_objects/dataview/setbigint64/index.md

metadata

title: DataView.prototype.setBigInt64()
short-title: setBigInt64()
slug: Web/JavaScript/Reference/Global_Objects/DataView/setBigInt64
page-type: javascript-instance-method
browser-compat: javascript.builtins.DataView.setBigInt64
sidebar: jsref

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()")}}

// 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

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")}}