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

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:133.0) Gecko/20100101 Firefox/133.0

Browser: Firefox 133

Operating system: Windows

Device Platform: Desktop

Date tested: one year ago

Test name	Executions per second
✓ Direct	29,231,314 Ops/sec
Through DataView	1,580,352 Ops/sec
With BigInt	1,179,034 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)

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

Through DataView

Direct

With BigInt