Functions are one of the most important concepts in JavaScript. They allow you to group code into reusable blocks that can be called whenever needed. Functions make your code modular, organized, and easier to maintain.
In this blog, we’ll explain different types of functions with examples.
⭐ What Is a Function?
A function is a block of code designed to perform a particular task. It can take inputs, called parameters, and return an output using the return statement.
Basic Example
function greet(name) {
return `Hello, ${name}!`;
}
console.log(greet("Sagar")); // Hello, Sagar!
⭐ 1. Function Declaration
Also called named functions, declared using the function keyword.
Example
function add(a, b) {
return a + b;
}
console.log(add(5, 10)); // 15
⭐ 2. Function Expression
Functions can also be stored in a variable.
Example
const multiply = function(x, y) {
return x * y;
};
console.log(multiply(5, 4)); // 20
⭐ 3. Arrow Functions (ES6)
Arrow functions provide a shorter syntax.
Example
const square = n => n * n;
console.log(square(5)); // 25
⭐ 4. Anonymous Functions
Functions without a name, often used as callbacks.
Example
setTimeout(function() {
console.log("This runs after 2 seconds");
}, 2000);
⭐ 5. Parameters and Arguments
- Parameters are placeholders in function definition.
- Arguments are values passed when calling the function.
Example
function greet(firstName, lastName) {
return `Hello, ${firstName} ${lastName}!`;
}
console.log(greet("Sagar", "Sidana")); // Hello, Sagar Sidana!
⭐ 6. Return Statement
Functions can return a value using return. If no return is specified, it returns undefined.
Example
function add(a, b) {
return a + b;
}
let sum = add(10, 20);
console.log(sum); // 30
⭐ 7. Immediately Invoked Function Expression (IIFE)
Functions that run immediately after creation.
Example
(function() {
console.log("IIFE runs automatically!");
})();
⭐ Why Functions Are Important
- Reusable code blocks
- Improve readability and structure
- Reduce redundancy
- Handle events and callbacks
- Form the foundation of object-oriented and functional programming
⭐ Conclusion
Functions are the backbone of JavaScript programming. Learning how to declare, call, and use functions efficiently is essential for building both simple scripts and complex applications.
📌 Citations
🔗 View other articles about Javascript:
https://savanka.com/category/learn/js/
🔗 External Javascript Documentation:
https://www.w3schools.com/js/