function titleCase(str) {
    //split sentence into array
    //find first letter of each string
    //change letter to caps
    //change array back into string
    var arr = str.split(' ');
    var newArr = []
    arr.map(function(item) {
       //item.replace(/^./, item[0].toUpperCase);
       newArr.push(item.toLowerCase().replace(/^./, item[0].toUpperCase()));
    });

    return newArr.join(' ');
}

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