FCC.js

function titleCase(str) {
  var list = str.split(' ');
  
  var newList = list.map(function(arg){
    var firstString = arg[0];
    var restString = arg.split(arg[0]).join('');
    
    
    firstString = firstString.toUpperCase();    
    restString = restString.toLowerCase();    
    return firstString + restString;
  });
  
    
  str = newList.join(' ');  
  return str;
}

titleCase("I'm a little tea pot");