How to use logic operator in Regex x <= y in Javascript

Question

Hello i have regex like this

^[\d]{4,5}([;]\d{4,5})*$|(^[\d]{4,4}([:]\d{4,5})$)|^[\d]{4,5}(\s[;]\s\d{4,5})*$|(^[\d]{4,4}(\s[:]\s\d{4,5})$)

I need effect like this:

• 12345 : 12345 - allowed

• 12345 : 1234 - not allowed

• 12345 : 12344 - not allowed

• 1234 : 1235 - allowed

• 1234 : 12345 - allowed

Generally - left <= right

Rest can be stay

Someone know how to resolve this problem?

Answer 1

The problem you describe cannot be described by a regular language, as such I doubt this can be solved with a regex. You could however solve this easily in JS:

 const [a, b] = str.split(":");
 if(+a <= +b) /*...*/