Question

I’m afraid that refinement on a match of a user-input string will result in an error, since matching with a regex that has the g flag set and doesn’t match the string will return null, which is unrefinable.

So I’m left with the two following options, and as far as I can tell, they’re identical. But I just want to make sure I’m understanding it properly.

    var tldMatcher = /[^.]+\.?$/g
      , tld = str.match(tldMatcher) ? str.match(tldMatcher)[0] : null;

…and…

    var tldMatcher = /[^.]+\.?$/g
      , tld = str.match(tldMatcher) && str.match(tldMatcher)[0];

Any thoughts?

Answer 1

Personally I always use || [] when I use .match with g. That is:

var matches = str.match(/regex/g) || [];

This ensures matches will always be an array of strings (but possibly empty). In your case it could be done like this:

var tldMatcher = /[^.]+\.?$/g
  , tld = (str.match(tldMatcher) || [])[0];