JavaScript - Functions

A JavaScript function is a reusable block of code that accepts inputs (arguments), processes them, and returns a value. Functions are declared using the "function" keyword, followed by a name and a set of parentheses that may include parameters. Functions are executed by calling the function name and passing in arguments.


function greeting(name) {

  return "Hello, " + name;


let greet = greeting("John");

console.log(greet); // Output: "Hello, John"

Functions can also be defined using anonymous functions, known as function expressions.


let greet = function (name) {

  return "Hello, " + name;


console.log(greet("John")); // Output: "Hello, John"

JavaScript functions can be used to simplify complex logic, to reduce code duplication, and to break down a large codebase into smaller, manageable parts.