Google spreadsheets custom function code not working: =RootDomain -

hi trying program google spreadsheets custom function. receives range , spits out clean rootdomain. ran "too many executions" - have run on whole sheet. added range.

now feedback "internal error function" ....

help appreciated .... must possible!

/**  * generates clean root domains  *  * @param {input} input value change root domain.  * @return clean root domain.  * @rootdomain  */ function rootdomain(input) {   if (input == null) return '';   if (input.map) {            // test whether input array.     return input.map(rootdomain); // recurse on array if so.   } else {     if (input = '') return '';     regex = new regexp(/((www)\.)?.*(\w+)\.([\w\.]{2,6})/);     return regex.exec(input)[0].replace(/^http(s)?:\/\//i, "").replace(/^www\./i, "").replace(/\/.*$/, "");   } } 

do instead:

function rootdomain(input) {   if (input == null || input === '') {    return '';   } else if (input.map) {            // test whether input array.   return input.map(rootdomain); // recurse on array if so.   }     var regex = new regexp(/((www)\.)?.*(\w+)\.([\w\.]{2,6})/);     return regex.exec(input)[0].replace(/^http(s)?:\/\//i, "").replace(/^www\./i, "").replace(/\/.*$/, "");   }