How does Stack Overflow generate its SEO-friendly URLs?

Question

What is a good complete regular expression or some other process that would take the title:

How do you change a title to be part of the URL like Stack

Answer 1

I know it's very old question but since most of the browsers now support unicode urls I found a great solution in XRegex that converts everything except letters (in all languages to '-').

That can be done in several programming languages.

The pattern is \\p{^L}+ and then you just need to use it to replace all non letters to '-'.

Working example in node.js with xregex module.

var text = 'This ! can @ have # several $ letters % from different languages such as עברית or Español';

var slugRegEx = XRegExp('((?!\\d)\\p{^L})+', 'g');

var slug = XRegExp.replace(text, slugRegEx, '-').toLowerCase();

console.log(slug) ==> "this-can-have-several-letters-from-different-languages-such-as-עברית-or-español"