// 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