anchor.diff:        domain = 'facebook';
       }
       return domain;
  +  };
  +
  +  function s3Object(uri){
  +    if (url.hostname === 's3.amazonaws.com'){
  +      return '/' + uri.pathname.split('/').slice(2).join('/');
  +    } else {
  +      return uri.pathname;
  +    }
     };
   
     function URI(url){
  
positive.code:     return null;
    };
  
    function urlDomain(host){
      var domain = 'other';
      if (/s3.amazonaws.com/i.test(host)){
  
negative.code:   };
  
    function generateEndpoint(source, modifiers){
      var uri, cdn, mods, path;
  
      uri = source || URI(source);
      cdn = IR.CDN.replace(/\/$/, '');
      mods = modStr(uri, modifiers);
      path = buildPath(uri, modifiers);
  
      return cdn + mods + path;
    };
  
    function modSet(key){
      var k, v;
      for (k in IR.modifiers){
        v = IR.modifiers[k];
        if (k === key || v.alias === key){
          return v;
        }
      }
      return null;
    };
  
    function sourceOption(key){
  