Type of function

#javascript #beginners

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()