I have to add validation for card expiry where I need to show an error message if the card is about to expire within 3 month's from current date

ex:

(month/year)1221 input --> false (invalid)
1121 input --> false (invalid)
122 input --> false (invalid)
221 input --> true (valid) 
222 input --> true (valid) 

From the backend this is the value I am getting value = 424 --> 4 is the month and 24 is the year which is valid and if from backend I am getting 1121 ---> 11 is the month and 21 is the year which is invalid

How to validate if the date 1121 is within 3 months?

Below is the solution I am using but I don't find other solutions

const d = new Date();
let today = d.getDate();
expValue = 424;
const originalValue = expValue.toString().split(/(?=(?:.{2}) $)/g);
if (
  originalValue[0] >= today.month.toString()   3 ||
  originalValue[1] === today.year.toString()
) {
  return this.sanitizer.bypassSecurityTrustHtml(
    '<span >'  
    ('0'   originalValue[0]).slice(-2)  
    '/'  
    originalValue[1]  
    '</span>'
  );
} else {
  return this.sanitizer.bypassSecurityTrustHtml(
    ('0'   originalValue[0]).slice(-2)   '/'   originalValue[1]
  );
}
}

<iframe name="sif1" sandbox="allow-forms allow-modals allow-scripts" frameborder="0"></iframe>

CodePudding user response：

Using the original inputs you gave, you can do something like this:

let inputs = ['12/21', '11/21', '01/22', '02/21', '12/22'];

const parseDate =(e)=>{ return new Date(e.replace('/', '/1/')); };

const getDiff = (e)=>{ 
  let curr = new Date();
  let dt = parseDate(e);
  return (dt.getMonth() - curr.getMonth()   
  (12 * (dt.getYear() - curr.getYear()))) > 3;
}

inputs.forEach(el=>console.log(`${el} >> ${getDiff(el)}`));

<iframe name="sif2" sandbox="allow-forms allow-modals allow-scripts" frameborder="0"></iframe>

If your inputs are in a different format or if you have to account for strings that aren't always the same length you might have to adjust the parseDate function. If you are working with a variable length string without the included "/", then you might try something like this, using the new inputs you gave:

let inputs = ['1221', '1121', '122', '221', '222'];

const parseDate =(e)=>{ 
  if(e.length==3) { e = '0' e; }
  return new Date(`${e.substring(0,2)}/1/${e.slice(-2)}`); 
};

const getDiff = (e)=>{ 
  let curr = new Date();
  let dt = parseDate(e);
  return (dt.getMonth() - curr.getMonth()   
  (12 * (dt.getYear() - curr.getYear()))) > 3;
}

inputs.forEach(el=>console.log(`${el} >> ${getDiff(el)}`));

<iframe name="sif3" sandbox="allow-forms allow-modals allow-scripts" frameborder="0"></iframe>

I modify the parseDate function to pad the string if the length is 3 (I think it's always going to be 3 or 4), then create a date from the first two characters and the last two characters, then return that, and everything else is the same.

CodePudding user response：

I think the best way to go at this is to translate dates into units that are suited to the problem. JS date getYear() gives months since 1990, and that's a practically useful common unit.

Put the input string date and the current date into units of months since 1990, then compare...

const monthsSince1900 = string => {
  let chars = string.split('');
  let month =  chars.slice(0, -2).join('');
  let year =  chars.slice(-2).join('');
  return 12 * (100   year)   month
};

const currentMonthsSince1990 = () => {
  let d = new Date();
  return 12 * d.getYear()   d.getMonth()   1;
}

const isExpiryValid = string => {
  let now = currentMonthsSince1990()
  let exp = monthsSince1900(string);
  return exp > now   3
}

console.log(isExpiryValid('1121'));  // 11/21 will expire soon
console.log(isExpiryValid('1221'));  // 12/21 will expire soon
console.log(isExpiryValid('122'));   // 1/22 will expire soon
console.log(isExpiryValid('222'));   // 2/22 is good
console.log(isExpiryValid('322'));   // 3/22 is good

<iframe name="sif4" sandbox="allow-forms allow-modals allow-scripts" frameborder="0"></iframe>