MY DuitNow QR Code Generator Sample

duitnow.js

String.prototype.padLeft = function (n, str) {
  if (n < String(this).length) {
    return this.toString();
  }
  else {
    return Array(n - String(this).length + 1).join(str || '0') + this;
  }
}

function crc16(s) {
  var crcTable = [0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50a5,
    0x60c6, 0x70e7, 0x8108, 0x9129, 0xa14a, 0xb16b,
    0xc18c, 0xd1ad, 0xe1ce, 0xf1ef, 0x1231, 0x0210,
    0x3273, 0x2252, 0x52b5, 0x4294, 0x72f7, 0x62d6,
    0x9339, 0x8318, 0xb37b, 0xa35a, 0xd3bd, 0xc39c,
    0xf3ff, 0xe3de, 0x2462, 0x3443, 0x0420, 0x1401,
    0x64e6, 0x74c7, 0x44a4, 0x5485, 0xa56a, 0xb54b,
    0x8528, 0x9509, 0xe5ee, 0xf5cf, 0xc5ac, 0xd58d,
    0x3653, 0x2672, 0x1611, 0x0630, 0x76d7, 0x66f6,
    0x5695, 0x46b4, 0xb75b, 0xa77a, 0x9719, 0x8738,
    0xf7df, 0xe7fe, 0xd79d, 0xc7bc, 0x48c4, 0x58e5,
    0x6886, 0x78a7, 0x0840, 0x1861, 0x2802, 0x3823,
    0xc9cc, 0xd9ed, 0xe98e, 0xf9af, 0x8948, 0x9969,
    0xa90a, 0xb92b, 0x5af5, 0x4ad4, 0x7ab7, 0x6a96,
    0x1a71, 0x0a50, 0x3a33, 0x2a12, 0xdbfd, 0xcbdc,
    0xfbbf, 0xeb9e, 0x9b79, 0x8b58, 0xbb3b, 0xab1a,
    0x6ca6, 0x7c87, 0x4ce4, 0x5cc5, 0x2c22, 0x3c03,
    0x0c60, 0x1c41, 0xedae, 0xfd8f, 0xcdec, 0xddcd,
    0xad2a, 0xbd0b, 0x8d68, 0x9d49, 0x7e97, 0x6eb6,
    0x5ed5, 0x4ef4, 0x3e13, 0x2e32, 0x1e51, 0x0e70,
    0xff9f, 0xefbe, 0xdfdd, 0xcffc, 0xbf1b, 0xaf3a,
    0x9f59, 0x8f78, 0x9188, 0x81a9, 0xb1ca, 0xa1eb,
    0xd10c, 0xc12d, 0xf14e, 0xe16f, 0x1080, 0x00a1,
    0x30c2, 0x20e3, 0x5004, 0x4025, 0x7046, 0x6067,
    0x83b9, 0x9398, 0xa3fb, 0xb3da, 0xc33d, 0xd31c,
    0xe37f, 0xf35e, 0x02b1, 0x1290, 0x22f3, 0x32d2,
    0x4235, 0x5214, 0x6277, 0x7256, 0xb5ea, 0xa5cb,
    0x95a8, 0x8589, 0xf56e, 0xe54f, 0xd52c, 0xc50d,
    0x34e2, 0x24c3, 0x14a0, 0x0481, 0x7466, 0x6447,
    0x5424, 0x4405, 0xa7db, 0xb7fa, 0x8799, 0x97b8,
    0xe75f, 0xf77e, 0xc71d, 0xd73c, 0x26d3, 0x36f2,
    0x0691, 0x16b0, 0x6657, 0x7676, 0x4615, 0x5634,
    0xd94c, 0xc96d, 0xf90e, 0xe92f, 0x99c8, 0x89e9,
    0xb98a, 0xa9ab, 0x5844, 0x4865, 0x7806, 0x6827,
    0x18c0, 0x08e1, 0x3882, 0x28a3, 0xcb7d, 0xdb5c,
    0xeb3f, 0xfb1e, 0x8bf9, 0x9bd8, 0xabbb, 0xbb9a,
    0x4a75, 0x5a54, 0x6a37, 0x7a16, 0x0af1, 0x1ad0,
    0x2ab3, 0x3a92, 0xfd2e, 0xed0f, 0xdd6c, 0xcd4d,
    0xbdaa, 0xad8b, 0x9de8, 0x8dc9, 0x7c26, 0x6c07,
    0x5c64, 0x4c45, 0x3ca2, 0x2c83, 0x1ce0, 0x0cc1,
    0xef1f, 0xff3e, 0xcf5d, 0xdf7c, 0xaf9b, 0xbfba,
    0x8fd9, 0x9ff8, 0x6e17, 0x7e36, 0x4e55, 0x5e74,
    0x2e93, 0x3eb2, 0x0ed1, 0x1ef0];

  var crc = 0xFFFF;
  var j, i;

  for (i = 0; i < s.length; i++) {

    c = s.charCodeAt(i);
    if (c > 255) {
      throw new RangeError();
    }
    j = (c ^ (crc >> 8)) & 0xFF;
    crc = crcTable[j] ^ (crc << 8);
  }

  return ((crc ^ 0) & 0xFFFF).toString(16).toUpperCase().padStart(4, '0');
}


function generateDuitNowStr( opts ) {

  let p = [
    { id: '00', value: '02' },                    // ID 00: Payload Format Indicator, PayNow is using 01, but DuitNow is using 02
    {
      id: '26', value:                            // ID 26: Merchant Account Info Template
        [
          { id: '00', value: 'A0000006150001' },    // DuitNow Application Identifier
          { id: '01', value: opts.app || '588734' },// unknown value, 588734 is from MAE app
          { id: '02', value: opts.account }         // unknown Account Number format       
        ]
    },
    { id: '52', value: opts.category || '0000' }, // ID 52: Merchant Category Code
    { id: '53', value: '458' },                   // ID 53: Currency. MYR is 458
    { id: '58', value: 'MY' },                    // ID 58: 2-letter Country Code (MY)
    { id: '59', value: opts.name ? opts.name.substring(0, 25) : 'NA' }, // ID 59: Merchant Name
    { id: '60', value: opts.city ? opts.city.substring(0, 15) : 'MY' } // ID 60: Merchant City
  ]

  // add Merchant Postcode
  if (opts.postcode) {
    p.push({ id: '61', value: opts.postcode })
  }

  // add Amount if any
  if (opts.amount) {
    p.push({ id: '01', value: '12' }) // ID 01: Point of Initiation Method 11: static, 12: dynamic
    p.push({ id: '54', value: opts.amount.toFixed(2) }) // ID 54: Transaction Amount
  } else {
    p.push({ id: '01', value: '11' }) // ID 01: Point of Initiation Method 11: static, 12: dynamic
  }

  // add Expiry Datetime
  if (opts.expiry) {
    p[p.findIndex(a => a.id == '26')].value.push({ id: '03', value: opts.expiry }) // Expiry datetime in Unix time in miliseconds
  }

  // add Ref Numbers
  if (opts.ref || opts.ref3 || opts.ref5 || opts.ref6 || opts.ref7 || opts.ref8) {

    let refObj = p.find(x => x.id === '62')

    if (!refObj) {
      refObj = { id: '62', value: []}
    }

    if (opts.ref) {
      refObj.value.push({ id: '01', value: opts.ref }) // ID 01: Bill Number
    }

    if (opts.ref3) {
      refObj.value.push({ id: '03', value: opts.ref3 }) // ID 03: Store Label 
    }

    if (opts.ref5) {
      refObj.value.push({ id: '05', value: opts.ref5 }) // ID 05: Reference Label
    }

    if (opts.ref6) {
      refObj.value.push({ id: '06', value: opts.ref6 }) // ID 06: Customer Label 
    }

    if (opts.ref7) {
      refObj.value.push({ id: '07', value: opts.ref7 }) // ID 07: Terminal Label 
    }

    if (opts.ref8) {
      refObj.value.push({ id: '08', value: opts.ref8 }) // ID 08: Purpose of Transaction
    }

    p.push(refObj)
  }

  // add Extra Ref Number
  if (opts.ref82) {
    p.push({ id: '82', value: opts.ref82 })
  }

  // sorting object by ID
  p.map((q) => Array.isArray(q.value) ? q.value.sort((a, b) => a.id.localeCompare(b.id)) : q)
  p.sort((a, b) => a.id.localeCompare(b.id))

  // start generating QR string
  let str = p.reduce((final, current) => {
    if (Array.isArray(current.value)) { //nest loop
      current.value = current.value.reduce((f, c) => {
        f += c.id + c.value.length.toString().padLeft(2) + c.value;
        return f
      }, "")
    }
    final += current.id + current.value.length.toString().padLeft(2) + current.value;
    return final
  }, "")

  // Here we add "6304" to the previous string
  // ID 63 (Checksum) 04 (4 characters)
  // Do a CRC16 of the whole string including the "6304"
  // then append it to the end.
  str += '6304' + crc16(str + '6304');

  return str;

}

module.exports = {
  generateDuitNowStr
}

package.json

{
  "version": "1.0.0",
  "name": "duitnow-js",
  "main": "duitnow.js"
}

i made a JS library to decode EMVQR, https://github.com/natsu90/emvqr