Type of function

Using a function is a good way to contain spesific task so you can call it whenever you need, In simple term function is a block of code that is design to perform spesific task. Usually structure of function look like this

function functionName(argument_1, argument_2, argument_n){ // code to be executed  } 

There are various type of functions that you can use depending what your need

Named functions

Create function by giving it name, this is the most common way to create a function

function Add(num1,num2){ return num1+num2 } Add(2,3) 

Imediate Invoke functions

Call a function as soon as they are declared, the benefit of this function is no variable are created so doesn't take up space in the global object or global memory

(function(num1,num2){ return num1 + num2 })(2,3); 

Anonymous functions

It's the opposite of named functions, a functions without a name, however unlike Immediate invoke functions anonymous function are not executed as soon as they declared.

Usually we need anonymous functions when function is very short in size or when passing a function as an argument to another function such as inside setInverval

var sum = function(num1,num2) { return num1 + num2} sum(2,3) 

Recursive functions

A function that keeps calling itself until the conditions is failed

function countDown(number){ console.log(number) var newNumber = number -1; if(newNumber > 0){ countDown(newNumber) } } countdown(4) 

Method

Function that are part of an object called method

let person = { firstName:'John', lastName:'Snow', fullName:function(){ return `${this.firstName} ${this.lastName}` } } person.fullName()