Javascript Regex optional character

Question

I have a regex pattern that I'm using (got it from Stack Overflow) to extract a video ID from a vimeo URL:

var regExp = /http:\/\/(www\.)?vimeo.com\/(\d+)($|\/)/;     var match = url.match(regExp); 

I need it to work whether http or https is specified. I've tried

var regExp = /http(s)?:\/\/(www\.)?vimeo.com\/(\d+)($|\/)/; 

But this fails on both http and https.

Help a brother out.

Answer 1

It fails because you are creating an extra capturing group, meaning that the capturing group indexes will not be the same as before.

To make the s optionnal without creating a capturing group, you can simply add ?, you do not need the parenthesis.

/https?:\/\/(www\.)?vimeo.com\/(\d+)($|\/)/ 

To create a non-capturing group, you can use (?:), but that's not necessary here, just showing for the example:

/http(?:s)?:\/\/(www\.)?vimeo.com\/(\d+)($|\/)/