gistfile1.js

/*jslint regexp: true, sloppy: true, maxerr: 50, indent: 2 */

function parseURI(url) {
  var m = String(url).match(/^([^:\/?#]+:)?(\/\/(?:[^:@]*(?::[^:@]*)?@)?(([^:\/?#]*)(?::(\d*))?))?([^?#]*)(\?[^#]*)?(#[\s\S]*)?/);
  // authority = '//' + user + ':' + pass '@' + hostname + ':' port
  return (m ? {
    href     : m[0] || '',
    protocol : m[1] || '',
    authority: m[2] || '',
    host     : m[3] || '',
    hostname : m[4] || '',
    port     : m[5] || '',
    pathname : m[6] || '',
    search   : m[7] || '',
    hash     : m[8] || ''
  } : null);
}

function absolutizeURI(base, href) {// RFC 3986

  function removeDotSegments(input) {
    var output = [];
    input.replace(/^(\.\.?(\/|$))+/, '')
         .replace(/\/(\.(\/|$))+/g, '/')
         .replace(/\/\.\.$/, '/../')
         .replace(/\/?[^\/]*/g, function (p) {
      if (p === '/..') {
        output.pop();
      } else {
        output.push(p);
      }
    });
    return output.join('');
  }

  href = parseURI(String(href || '').replace(/^\s+|\s+$/g, ''));
  base = parseURI(String(base || '').replace(/^\s+|\s+$/g, ''));
  if (href === null || base === null) {
    return null;
  }
  var res = {};
  if (href.protocol || href.authority) {
    res.authority = href.authority;
    res.pathname  = removeDotSegments(href.pathname);
    res.search    = href.search;
  } else {
    if (!href.pathname) {
      res.pathname = base.pathname;
      res.search   = href.search || base.search;
    } else {
      if (href.pathname.charAt(0) === '/') {
        res.pathname = removeDotSegments(href.pathname);
      } else {
        if (base.authority && !base.pathname) {
          res.pathname = removeDotSegments('/' + href.pathname);
        } else {
          res.pathname = removeDotSegments(base.pathname.slice(0, base.pathname.lastIndexOf('/') + 1) + href.pathname);
        }
      }
      res.search = href.search;
    }
    res.authority = base.authority;
  }
  res.protocol = href.protocol || base.protocol;
  res.hash     = href.hash;
  return res.protocol + res.authority + res.pathname + res.search + res.hash;
}