​

function greet(firstName, lastName) {

  var _firstName = capitaliseFirstLetter(firstName),

      _lastName = capitaliseFirstLetter(lastName),

      greeting = buildGreeting(_firstName, _lastName);

  console.log(greeting);

} 

​

function buildGreeting(firstName, lastName) {

  return "Good Morning " + firstName + " " + lastName;

}

​

function capitaliseFirstLetter(string) {

    return string.charAt(0).toUpperCase() + string.slice(1);

}

​

greet('john', 'smith');

​