firstClassExample2.js

// 2. Pass a function as a parameter
function sayHello() {
   return "Hello, ";
}
function greeting(helloMessage, name) {
  console.log(helloMessage() + name);
}

greeting(sayHello, "JavaScript!");

// 3. Return a function
function sayHello() {
   return function() {
      console.log("Hello!");
   }
}