using the proper algorithm you shouldn't run into that issue. But that's a valid concern. I'll add it to the description.

I agree with this. My code works fine until the last random number where it takes too long to run. As a beginner, I have no idea how to fix this so I think it is more appropriate as a lower kyu level if that last part is to be left in.

There is no "output" for this kata. A given string is tested against the regex (or vis versa, depending on how you look at it). So if you match anything, the test will be successful.

So for example:

var Mod4 = /\[\+05620\]/g;
Mod4.test("[+05620]") // will return `true`, meaning the given string has a valid mod4 within it

I am Super confused of what needs to be the output. Can someone explain me with an clear example?

Hi Redmega,

Don't you think testing the solution with numbers like 85241263, is bit of an overkill for new programmers like me. My solution works fine till earlier 8 digit numbers, but number close to 10 crore is too much. Atleast it should be mentioned in the description, so that we can concentrate on the optimization of the program while writing the code itself. If this limitation is placed this should an higher level kata rather than an 7 kyu.