Difference Between Function Declarations and Function Expressions

In JavaScript, functions can be defined using Function Declarations or Function Expressions. While they serve similar purposes, they differ in terms of syntax, behavior, and hoisting.

Function Declarations

Defined using the function keyword followed by the function name.
Can be called before their definition due to hoisting.

Example:

        
function greet() {
    console.log("Hello from Function Declaration!");
}

greet(); // Output: Hello from Function Declaration!

Output: Hello from Function Declaration!

Function Expressions

Defined by assigning a function to a variable.
Not hoisted, so they cannot be called before their definition.

Example:

        
const greet = function() {
    console.log("Hello from Function Expression!");
};

greet(); // Output: Hello from Function Expression!

Output: Hello from Function Expression!

Key Differences

Aspect	Function Declaration	Function Expression
Syntax	`function name() { ... }`	`const name = function() { ... }`
Hoisting	Can be called before its definition.	Cannot be called before its definition.
Use Case	Used for named reusable functions.	Used for anonymous functions or assigning functions to variables.