Question

There are two URLs I have:

http://localhost:65043/home/create/

http://localhost:65043/home/create/2

I want to check that the ID exists in the URL or not. If yes, then I need to parse them, otherwise I got 0.

How I can get the ID from the URL and if they not, have that get 0 from that and return a thing that shows that “It is new. No ID exists with URL”

How I can do this?

Answer 1

 // Grab the complete URL
 var loc = document.location.href;

 // Strip the things we don't need
 loc = loc.replace('http://localhost:65043/home/create/','')

 // Make the remnants a number 
 var id = parseInt(loc, 10);

 // Test if the remnants are a number or assign 0
 id = isNaN(id) ? 0 : id;

If you want to do it all at once in a silly way, you can reverse the URL and put it into a parseInt. Then test if it is a number. So you don’t need to know where the URL is running, only to check if the last part of the path is an ID.

var id = parseInt(parseInt(
    document.location.href
    .split('')
    .reverse()
    .join(''), 10) 
      .toString()
      .split('')
      .reverse()
      .join(''), 10) | 0;

But as you can see, that gets quite unreadable. (And is about four times slower.)

It basically:

• Reverses the URL
• Puts it in parseInt (since that tries to parse an int from left to right it seems quite fitting then)
• Then I have to reverse the number (as a string) again otherwise it was backwards, and parse it again as int
• Do an OR operation with 0 that will return 0 if all previous operations resulted in not a number.