function bigIntToBigEndianBytesLoopParseInt(value) {

    const hex = value.toString(16).padStart(16, '0');

    const bytes = new Uint8Array(8);

    for (let i = 0; i < 8; i++) {

        bytes[i] = parseInt(hex.slice(i * 2, i * 2 + 2), 16);

    }

    return bytes;

}

​

function bigIntToBigEndianBytesLoopConstructor(value) {

    const hex = value.toString(16).padStart(16, '0');

    const bytes = new Uint8Array(8);

    for (let i = 0; i < 8; i++) {

        bytes[i] = Number(hex.slice(i * 2, i * 2 + 2), 16);

    }

    return bytes;

}

​

function bigIntToBigEndianBytesDataView(value) {

    const buf = new ArrayBuffer(8);

    const view = new DataView(buf);

​

    view.setBigUint64(0, value);

    return new Uint8Array(buf);

}

​

function bigIntToUint8ArrayDirectConstructor(value) {

    const result = new Uint8Array(8);

    result[7] = Number(value & 0xffn);

    result[6] = Number((value >> 8n) & 0xffn);

    result[5] = Number((value >> 16n) & 0xffn);

    result[4] = Number((value >> 24n) & 0xffn );

    result[3] = Number((value >> 32n) & 0xffn);

    result[2] = Number((value >> 40n) & 0xffn);

    result[1] = Number((value >> 48n) & 0xffn);

    result[0] = Number((value >> 56n) & 0xffn);

    return result;

}

​

// Added by trincot: first split BigInt into two numbers (32 bit), then work with those only

function bigIntToUint8ArrayDirectConstructor2(value) {

    const result = new Uint8Array(8);

    const low = Number(value & 0xffffffffn);

    const high = Number((value >> 32n) & 0xffffffffn); 

    result[7] = low & 0xff;

    result[6] = (low >> 8) & 0xff;

    result[5] = (low >> 16) & 0xff;

    result[4] = (low >> 24) & 0xff;

    result[3] = high & 0xff;

    result[2] = (high >> 8) & 0xff;

    result[1] = (high >> 16) & 0xff;

    result[0] = (high >> 24) & 0xff;

    return result;

}

​

function bigIntToUint8ArrayDirectParseInt(value) {

    const result = new Uint8Array(8);

    result[7] = parseInt(value & 0xffn);

    result[6] = parseInt((value >> 8n) & 0xffn);

    result[5] = parseInt((value >> 16n) & 0xffn);

    result[4] = parseInt((value >> 24n) & 0xffn );

    result[3] = parseInt((value >> 32n) & 0xffn);

    result[2] = parseInt((value >> 40n) & 0xffn);

    result[1] = parseInt((value >> 48n) & 0xffn);

    result[0] = parseInt((value >> 56n) & 0xffn);

    return result;

}