5 Key Points About JavaScript Functions

1. Reusable Blocks of Code
   A function is a block of code designed to perform a specific task. Once defined, it can be called and reused throughout your application with different inputs.

2. First-Class Citizens
   In JavaScript, functions are treated as first-class objects. This means you can store them in variables, pass them as arguments to other functions (callbacks), and return them from other functions.

3. Multiple Syntax Options
   JavaScript provides several ways to define functions:

   • Function Declaration: function greet() {}
   • Function Expression: const greet = function() {};
   • Arrow Function: const greet = () => {};

4. Parameters and Return Values
   Functions accept inputs called parameters and can output a value using the return statement. If no return statement is defined, the function returns undefined by default.

5. Scope and Closures
   Variables defined inside a function are locally scoped and cannot be accessed from the outside. Additionally, functions create closures, meaning an inner function retains access to the variables of its parent function even after the parent function has executed.