I am attempting to extract Smith from name into lastName.
function reggie(){
  var name = "JohnSmith";
  var first = "John";
  var regExp = new RegExp("(?:"+first+")(w+)", "gi");
  var lastName = regExp.exec(name);
  //Logger.log(lastName); // in google apps
  console.log(lastName);
}
reggie() 
    