Function Expression & Function Statement in Javascript

In JavaScript, functions can be defined using two main ways: function expressions and function statements (also known as function declarations). Both approaches allow you to create reusable blocks of code that can be invoked later in your program.

Function Expression:

A function expression offers an alternative approach to defining a function by assigning it to a variable instead of using the traditional function declaration. The function is created and assigned during the execution of the code. Function expressions are often used for creating anonymous functions or when the function needs to be assigned to a variable for later use.

For Ex.

Function Statement (Function Declaration):

A function statement, or function declaration, is a more traditional way to define a function. It starts with the function keyword, followed by the function name, a list of parameters enclosed in parentheses, and the function body. Function declarations are hoisted in JavaScript, meaning they can be used before their actual definition in the code.

Syntax:

Example:

Differences between Function Expression and Function Statement:

1. Hoisting: Function declarations are hoisted, which means they can be used before their actual definition in the code. Unlike function declarations, function expressions are not hoisted and cannot be accessed or used before they are defined in the code.
2. Named vs. Anonymous: Function declarations must have a name, while function expressions can be either named or anonymous.
3. Assignment: Function declarations are bound to the variable name automatically, whereas function expressions need to be explicitly assigned to a variable.
4. Use cases:  Function expressions are commonly used for callback functions, closures, and as arguments to higher-order functions. Function declarations are typically used for standalone functions and when you need to create a reusable function for a specific task.

Both function expressions and function statements have their specific use cases, and the choice between them depends on the requirements and style of your code.