Functions in JavaScript

Learn how to create reusable blocks of code with functions.

What are Functions?

Functions are reusable blocks of code that perform a specific task. They help you organize your code, avoid repetition, and make your programs easier to understand and maintain.

Key Concept: Functions follow the DRY principle - Don't Repeat Yourself. Write once, use many times!

Function Declarations

The most common way to create a function is using a function declaration.

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Function Expressions

Functions can also be stored in variables. This is called a function expression.

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Arrow Functions

Arrow functions provide a shorter syntax for writing functions. They're especially useful for simple operations.

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Parameters and Arguments

Functions can accept parameters (inputs) and return values (outputs).

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Return Values

Functions can return a value using the return statement. If no return is specified, the function returns undefined.

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Challenge: Create a Calculator

Create a function called calculate that takes three parameters: two numbers and an operator (+, -, *, /). Return the result of the operation.

Your solution

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