// code example 1

var x = 7;

function getName(){
    console.log("Namaste JavaScript");
}

getName();
console.log(x);

Output:

Namaste JavaScript

7

// code example 2

getName();      // in most languages, both lines which are above their declaration will give error. Not in JS though. 
console.log(x); 

var x = 7;

function getName(){
    console.log("Namaste JavaScript");
}

Output:

Namaste JavaScript

undefined

// code example 3

getName();
console.log(x);

function getName(){
    console.log("Namaste JavaScript");
}

Output:

Namaste JavaScript

Error: x is not defined // note that not defined here and "undefined" in sample 2 are totally different.

• Not defined: We have not initialised the value for variable anywhere in the entire code and in memory space.
• Undefined:

Hoisting is a concept which enables us to extract values of variables and functions even before initialising/assigning value without getting error

// code example 4

function getName(){
    console.log("Namaste JavaScript");
}

console.log(getName)

Output:

f getName(){ console.log("Namaste JavaScript); }

// code example 5

getName();
console.log(x);
console.log(getName)

function getName(){
    console.log("Namaste JavaScript");
}

Output:

Namaste JavaScript

undefined

f getName(){ console.log("Namaste JavaScript); }

// code example 6

console.log(getName)

var getName = function () {
    console.log("Namaste JavaScript");
}

var getName = () => {  // use fat arrow function  
    console.log("Namaste JavaScript");
}

Output:

undefined //it is because they behave as variable and not function.

REASON OF WEIRDNESS

• The answer lies in the Global Exection Context. In the memory phase, the variables will be initialized as undefined and functions will get the whole function code in their memory.

• This is the reason why we are getting these outputs.