# Hoisting in JavaScript ~~~javascript //Example: 1 console.log(x) var x = 7; ~~~ In most of the programming languages it will through an error because we can't use a variable before declaring it. But JavaScript is different. The output will be : ~~~ undefined ~~~ ~~~javascript // Example: 2 console.log(x) ~~~ It will through : ~~~ ReferenceError: x is not defined ~~~ ~~~javascript // Example: 3 console.log(Hello); function Hello(){ console.log("Hello World"); } ~~~ ~~~ [Function: Hello] ~~~ Remember in JavaScript, Even before the code starts executing memory is being alocated to all variables and functions. Variables are undefined but not functions. In example 2 the output is not defined. Not defined means the variable is not present in the program. But undefined means it is present but not present in the scope. ~~~javascript // Example: 4 console.log(Hello); let Hello = () => { console.log("Hello World"); } ~~~ ~~~ undefined ~~~ ~~~javascript // Example: 5 Hello() let Hello = () => { console.log("Hello World"); } ~~~ ~~~ TypeError: Hello is not a function ~~~ In Example 4 and 5 we changed the function to an arrow function. In this case it will behave like a variable. Thats why in Example 4 it is saying undefined and in Example 5 not a function.