BigInt64Array

const buffer = new ArrayBuffer(24);
const bigint64 = new BigInt64Array(buffer);
bigint64[0] = 5886014448488689n;
bigint64[1] = 1881938909131133n;
bigint64[2] = 1898875537769492n;

bigint64[0] = 6118793953620967n;
console.log(bigint64);
// : BigInt64Array [6118793953620967n, 1881938909131133n, 1898875537769492n]

console.log(bigint64[2]);
// : 1898875537769492n

console.log(":", bigint64.length);
// : : 3

console.log(":", bigint64.byteLength);
// : : 24

console.log(":", bigint64.byteOffset);
// : : 0

bigint64.set([100n, 200n], 1);
console.log(bigint64);
// : BigInt64Array [6118793953620967n, 100n, 200n]

// 
const bigint64 = new BigInt64Array(2);
bigint64[0] = 42n;
console.log(bigint64[0]); // 42n
console.log(bigint64.length); // 2
console.log(bigint64.BYTES_PER_ELEMENT); // 8

// 
const x = new BigInt64Array([21n, 31n]);
console.log(x[1]); // 31n

//  TypedArray 
const y = new BigInt64Array(x);
console.log(y[0]); // 21n

// ArrayBuffer 
const buffer = new ArrayBuffer(64);
const z = new BigInt64Array(buffer, 8, 4);
console.log(z.byteOffset); // 8

// 
const iterable = (function* () {
  yield* [1n, 2n, 3n];
})();
const bigint64FromIterable = new BigInt64Array(iterable);
console.log(bigint64FromIterable);
// BigInt64Array [1n, 2n, 3n]