Summary  
This chapter covers how to define functions—specifying their declaration, name, parameters, body, and return value—to group and reuse logic with customizable inputs.

General domain of usage  
Game development


### Parts of a Function

- **Declaration**: starts with the function keyword;
- **Name**: identifies the function (e.g., `ninjaController`, `lootZigZag`).
- **Parameters**: variables inside parentheses that accept values when the function is called;
- **Body**: the block of code inside `{}` containing the function's actions;
- **Return value**: an optional value returned by the function. If omitted, the result is `undefined`.

### Example


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- `ninjaController` : controls the ninja by calling `lootBox(ninja)` twice and moving right four times;
- `lootBox` : groups a sequence of moves and sushi pickups into a reusable helper function;
- `ninja` parameter: represents the `ninja` object that provides methods like `goRight()`, `goUp()`, and `pickSushi()`.

Welcome to the JavaScript Ninja Course! This engaging and interactive course is designed to introduce you to the fundamentals of JavaScript programming through a fun and educational game. You'll guide a ninja through various challenges, using JavaScript to control movements and interact with objects like sushi. Starting with the basics, you'll learn how to navigate the map, pick up and place sushi, and gradually progress to more complex programming concepts such as functions, loops, and conditional statements. Each chapter offers hands-on practice to reinforce your learning, culminating in exciting challenges that test your skills. Whether you're a complete beginner or looking to sharpen your coding abilities, this course provides a comprehensive and enjoyable learning experience. Join us and become a coding ninja!

Learn to control the ninja using simple JavaScript commands. Move in different directions to navigate the grid. Pick up sushi by calling predefined actions. Solve small missions that reinforce sequencing and basic code execution.

Use movement commands to navigate more complex layouts. Pick up sushi and place it on specific cells. Combine movement and object manipulation to transport sushi across the grid. Solve multi-step missions that require planning, precision, and full control of the ninja's actions.

In the "Functions" section, you'll delve into the powerful JavaScript feature of creating and utilizing functions to streamline your code. You'll learn how to write functions to perform specific tasks, enhancing code reusability and clarity. By practicing decomposition, you'll break down complex problems into simpler functions, mastering the art of organized and efficient coding.

In the "Loops" section, you'll explore the essential JavaScript feature of loops, which allows you to execute repetitive tasks efficiently. You'll learn to implement both for loops and while loops, gaining the ability to automate actions and iterate over sequences. By mastering nested loops, you'll tackle more complex scenarios, enhancing your ability to write concise and powerful code.

In the "If-Else Statements" section, you'll learn how to use JavaScript's conditional logic to make decisions within your code. You'll explore how if-else statements allow your ninja to respond dynamically to different scenarios, enabling more intelligent and adaptable behavior. Through practical exercises, you'll apply these concepts to solve challenges, enhancing your ability to write responsive and decision-driven code.

In the "Challenges" section, you'll apply your JavaScript skills to tackle a series of engaging and complex problems. These challenges will test your understanding of loops, functions, and conditional logic as you guide your ninja to align columns, build letters, and traverse intricate patterns. By solving these puzzles, you'll refine your coding abilities and gain confidence in applying JavaScript to creative and real-world scenarios.

Writing Functions

Parts of a Function

Example

Solution