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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 generatePayNowStr( opts ) { | |
const p = [ | |
{ id: '00', value: '01' }, // ID 00: Payload Format Indicator (Fixed to '01') | |
{ id: '01', value: '12' }, // ID 01: Point of Initiation Method 11: static, 12: dynamic | |
{ | |
id: '26', value: // ID 26: Merchant Account Info Template | |
[{ id: '00', value: 'SG.PAYNOW' }, | |
{ id: '01', value: '2' }, // 0 for mobile, 2 for UEN. 1 is not used. | |
{ id: '02', value: opts.uen }, // PayNow UEN (Company Unique Entity Number) | |
{ id: '03', value: opts.editable.toString() }, // 1 = Payment amount is editable, 0 = Not Editable | |
{ id: '04', value: opts.expiry }] // Expiry date (YYYYMMDD) | |
}, | |
{ id: '52', value: '0000' }, // ID 52: Merchant Category Code (not used) | |
{ id: '53', value: '702' }, // ID 53: Currency. SGD is 702 | |
{ id: '54', value: opts.amount.toString() }, // ID 54: Transaction Amount | |
{ id: '58', value: 'SG' }, // ID 58: 2-letter Country Code (SG) | |
{ id: '59', value: 'COMPANY NAME' }, // ID 59: Company Name | |
{ id: '60', value: 'Singapore' }, // ID 60: Merchant City | |
{ | |
id: '62', value: [{ // ID 62: Additional data fields | |
id: '01', value: opts.refNumber // ID 01: Bill Number | |
}] | |
} | |
] | |
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; | |
} |
why it can't generate dynamic QR code any more?
Hi Cheng Kiang, are we able to set the expiry date to 10 minutes after the current time?
Based on the specifications that I used for this (and it's few years old now), it can only support down to the day. There might be a new version of the specifications, but I am not sure where to find it.
Regards CKThanks for the information. Since I'm using this to generate dynamic QR code for a form, can I check if I can set the expiry date to current date + 1 day? Eg: Current date is 20230814, I would like the qr code to expire on 20230815
Do your dynamic QR code still works? How can't get dynamic QR code now with default config { id: '01', value: '12' } ?
Hi Cheng Kiang, are we able to set the expiry date to 10 minutes after the current time?
Based on the specifications that I used for this (and it's few years old now), it can only support down to the day. There might be a new version of the specifications, but I am not sure where to find it.
Regards CKThanks for the information. Since I'm using this to generate dynamic QR code for a form, can I check if I can set the expiry date to current date + 1 day? Eg: Current date is 20230814, I would like the qr code to expire on 20230815
Do your dynamic QR code still works? How can't get dynamic QR code now with default config { id: '01', value: '12' } ?
I just tested and it works with the following:
const opts = {
uen: '+6512345678', // Change to a valid mobile number
editable: 0,
expiry: '20240402', // Expire on 2 Apr 2024
amount: 12.34,
refNumber: 'ABC123'
};
const qr = generatePayNowStr(opts);
If you are using a mobile number instead of a company UEN, you need to change line #80 of the gist to:
{ id: '01', value: '0' },
and also make sure it's a valid mobile number. If you put in a fake number, it won't work.
By the way, I noticed in your comment that your date is in the year 2023.
May I know can we limit a qr code for one transaction only? For example, once a user has scanned the QR code and paid, the QR code is expired and doesn't allow transaction anymore.
May I know can we limit a qr code for one transaction only? For example, once a user has scanned the QR code and paid, the QR code is expired and doesn't allow transaction anymore.
You need bank transaction API access for that.. The QR code has no way to know if it was even scanned at all... :)
I see, thank you for the answer.
This code only generates a string which you can pass to a QR Code generator to generate the QR code. To have colours, logos, etc., use a QR code generator which supports these features.