Run results for: JS number to UInt8Array 64-bit little endian

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/121.0.0.0 Safari/537.36

Browser: Chrome 121

Operating system: Mac OS X 10.15.7

Device Platform: Desktop

Date tested: 2 years ago

Direct

9.4M/s

Through DataView

2.4M/s

With BigInt

1.1M/s

View exact numbers

Test name	Executions per second
✓ Direct	9,409,328 Ops/sec
Through DataView	2,429,130 Ops/sec
With BigInt	1,143,533 Ops/sec

Script Preparation code:

function numberToUint8Array64LE_DataView(num) {
    const buf = new ArrayBuffer(8)
    const view = new DataView(buf)
    view.setUint32(0, num, true)
    view.setUint32(4, num >>> 32, true)
    return new Uint8Array(buf)
}

function numberToUint8Array64LE_direct(num) {
    const result = new Uint8Array(8)
    result[0] = num & 0xff
    result[1] = (num >>> 8) & 0xff
    result[2] = (num >>> 16) & 0xff
    result[3] = (num >>> 24) & 0xff
    result[4] = (num >>> 32) & 0xff
    result[5] = (num >>> 40) & 0xff
    result[6] = (num >>> 48) & 0xff
    result[7] = (num >>> 56) & 0xff
    return result
}

function numberToUint8Array64LE_bigint(num) {
    const bigIntValue = BigInt.asUintN(64, BigInt(num));
    const buffer = new ArrayBuffer(8);
    const dataView = new DataView(buffer);
    dataView.setBigUint64(0, bigIntValue, true);
    return Uint8Array.from(buffer.slice(0, 8));
}

Tests:

Through DataView
numberToUint8Array64LE_DataView(0xababababab)
Direct
numberToUint8Array64LE_direct(0xababababab)
With BigInt
numberToUint8Array64LE_bigint(0xababababab)