QR Bank Vietnam

 const generateCheckSum = (text) => {
    let crc = 0xffff;
    let polynomial = 0x1021;
    let bytes = new TextEncoder().encode(text);

    for (let b of bytes) {
        for (let i = 0; i < 8; i++) {
            let bit = ((b >> (7 - i)) & 1) === 1;
            let c15 = ((crc >> 15) & 1) === 1;
            crc <<= 1;
            if (c15 !== bit) {
                crc ^= polynomial;
            }
        }
    }
    return (crc & 0xffff).toString(16);
};

// All params must be a string
 const generateQRCode = (bankId, amount, bankAccount, message) => {
    const part12Builder = ""
        .concat("00")
        .concat(bankId.length.toString().padStart(2, "0"))
        .concat(bankId)
        .concat("01")
        .concat(bankAccount.length.toString().padStart(2, "0"))
        .concat(bankAccount);
    const part11Builder = ""
        .concat("0010A000000727")
        .concat("01")
        .concat(part12Builder.length.toString().padStart(2, "0"))
        .concat(part12Builder)
        .concat("0208QRIBFTTA");
    const part1Builder = ""
        .concat("38")
        .concat(part11Builder.length.toString().padStart(2, "0"))
        .concat(part11Builder);
    const part21Builder = ""
        .concat("08")
        .concat(message.length.toString().padStart(2, "0"))
        .concat(message);
    const part2 = ""
        .concat("5303704")
        .concat("54")
        .concat(amount.length.toString().padStart(2, "0"))
        .concat(amount)
        .concat("5802VN")
        .concat("62")
        .concat(part21Builder.length.toString().padStart(2, "0"))
        .concat(part21Builder);
    const builder = ""
        .concat()
        .concat("000201")
        .concat("010212")
        .concat(part1Builder)
        .concat(part2)
        .concat("6304");
    const qrcodeContent = builder.concat(generateCheckSum(builder).toUpperCase());
    return qrcodeContent;
};