js-function.js

// Function Statement 

greet(); // hoisting
function greet(){
    console.log('hi');
};

// FUNCTION EXPRESSION (ANONYMOUS)

anonymousGreet(); // undefined is not a function
anonymousGreet; // undefined
var anonymousGreet = function(){
    console.log('hi');    
};

// wrap in parentheses
(function(){
    console.log('hi');    
});

// IMMEDIATELY INVOKED FUNCTION EXPRESSIONS (IIFE)

var IIFEGreet = function(name){
    return 'hi ' + name;
}('John'); // hi John
IIFEGreet; // hi John
"hi John"; // hi John
IIFEGreet(); // IIFEGreet is not a function

// wrap in parentheses

(function(name){
    return 'hi ' + name;
}('John')); // hi John

(function(name){
    return 'hi ' + name;
})('John'); // hi John