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Types of Functions in JavaScript

Introduction

In this article, we will cover Types of functions in JavaScript. Before we start, Let's understand the objective of this demonstration, which tells what exactly will be covered in this article.

  • Named Functions
  • Anonymous Functions
  • Arrow Functions
  • IIFE (Immediately Invoked Function Expression)
  • Higher-Order Functions
  • Constructor Functions

So, Let's get started.

Named Functions

These are regular functions that are defined with a name and can be called by that name.

function displayName(name) {
console.log(`Hello, ${name}!`);
}

displayName("Vishal"); 
// Output: Hello, Vishal"));

Named function

Anonymous Functions

These are functions that do not have a name and are often used as arguments to other functions or assigned to variables.

const sum = function(a, b) {
return a + b;
}
console.log(sum(3, 5)); 
// Output: 8

Anonymous function

Arrow Function

Introduced in ECMAScript 6 (ES6), arrow functions provide a concise syntax for writing functions, especially when you want to use a simple one-liner.

const multiply = (x, y) => x * y;
console.log(multiply(4, 6)); 
// Output: 24

Arrow Function

IIFE (Immediately Invoked Function Expression)

These are self-invoking functions that execute as soon as they are defined.

(function (x, y, z) {  
   console.log(x);  
   console.log(y);  
   console.log(z);  
 })(100, 200, 300);  

// Output: 100
// Output: 200
// Output: 300

IIFE (Immediately Invoked Function Expression)

Higher-Order Functions

Functions that can accept other functions as arguments and/or return functions.

Eg: map(), filter(), reduce()

let arr = [5,10,15,20,25];
let newarr = arr.map((element)=> {
return element + 5;
})
console.log(newarr); 
// Output: [10,15,20,25,30]

Higher-Order function

Constructor Function

Functions used to create instances of objects are often used for defining classes and creating objects with shared properties and methods

function Person(name, age) {
this.name = name;
this.age = age;
}
const person = new Person("Vishal", 33);
console.log(person.name); 
console.log(person.age); 

// Output: Vishal
// Output: 33

Constructor function

Summary

In this article, I have tried to cover Types of functions in Javascript.


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