Slot Machine on Node.js Project Analysis
Tags: node, javascript
Published: 2024-05-28 12:51:41

## Project Structure

> A game written in pure Javascript and Node JS. 
> By author [a7ul](https://github.com/a7ul)

The Slot Machine project is organized into several key directories and files:

```
slot-machine-master/
├── .eslintrc
├── .gitignore
├── Procfile
├── README.md
├── index.js
├── package.json
├── yarn.lock
├── app/
│   ├── index.html
│   ├── main.js
│   ├── style.css
│   └── assets/
│       ├── Symbol_0.png
│       ├── Symbol_1.png
│       ├── Symbol_2.png
│       ├── Symbol_3.png
│       ├── Symbol_4.png
│       ├── Symbol_5.png
│       └── button.png
└── server/
    ├── handlers.js
    ├── helpers.js
    └── router.js
```

## Key Files and Directories
**1. Configuration Files**

- .eslintrc: Contains the [ESLint](https://eslint.org/) configuration for the project, ensuring code quality and consistency.
- .gitignore: Specifies files and directories that should be ignored by Git, preventing them from being committed to the repository.
- Procfile: Used by Heroku to declare the process types and commands to be executed.

**2. Project Metadata**

- package.json: Contains metadata about the project, including dependencies, scripts, and other configurations.
- yarn.lock: Ensures that the exact versions of dependencies are installed.

**3. Main Application Files**

- index.js: The entry point of the [Node.js](https://nodejs.org/en) application.
- README.md: Provides an overview of the project, installation instructions, and usage details.

**4. Frontend Application**

- app/index.html: The main HTML file for the front end.
- app/main.js: The primary JavaScript file for frontend logic.
- app/style.css: The stylesheet for the front end.
- app/assets/: Contains images used in the application, such as symbols for the slot machine and button images.

**5. Backend Logic**

- server/handlers.js: Contains handler functions for various routes.
- server/helpers.js: Includes helper functions used by the handlers.
- server/router.js: Defines the routing logic for the backend.

## Detailed File Analysis

**index.js**

```
const http = require('http');
const router = require('./server/router');

const PORT = process.env.PORT || 3000;

const server = http.createServer(router);

server.listen(PORT, () => console.log(`Server running at Port :${PORT}/`)); //eslint-disable-line no-console
```

This file is the main entry point of the Node.js application. It typically sets up the server and configures middleware and routes.

**package.json**
This file includes essential information about the project, such as the project name, version, and dependencies. For example, it lists the required npm packages and scripts for running and testing the application.

**README.md**
The README file provides a comprehensive guide on how to set up and run the project. It often includes installation instructions, a description of the project, and usage examples.

**app/index.html**

```
<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <title>Slot Machine</title>
    <link rel="stylesheet" href="./style.css">
  </head>
  <body>
    <div class="container">
      <div id="win-message">Press Button to Play</div>
      <div class="image-container">
        <img id="first-image" class="result-image" src="./assets/Symbol_1.png"/>
        <img id="second-image" class="result-image" src="./assets/Symbol_1.png"/>
        <img id="third-image" class="result-image" src="./assets/Symbol_1.png"/>
      </div>
      <div class="retry-button-container">
        <div id="message">Hidden Message</div>
        <img id="retry-button" src="./assets/button.png"/>
      </div>
    </div>
    <script src="./main.js"></script>
  </body>
</html>
```
This is the main HTML file for the frontend application. It includes the structure of the slot machine interface (worthy of the [best online casino providers](https://x-casino.org)), linking to the CSS and JavaScript files.

**app/main.js**

```
(function() {
  const ASSET_PATH = './assets'; // Path to the assets folder

  // Function to fetch the result from the server
  const fetchResult = () => {
    const responsePromise = window.fetch('/result', {method: 'get'})
      .then((rawResponse) => rawResponse.json()); // Parse the response as JSON
    return responsePromise;
  };

  // Function to retry and fetch a new result
  const retryNewResult = () => {
    setMessage(null); // Clear any existing messages
    fetchResult().then((response) => {
      const {result, bonus} = response; // Destructure the response
      setResultOnUI(result); // Update the UI with the result
      setWinMessage(result); // Display the win message based on the result
      checkBonus(bonus); // Check and handle the bonus
    }).catch((err)=>{
      setMessage(err.message); // Display error message if fetching fails
    });
  };

  // Function to set the win message based on the result
  const setWinMessage = (result) => {
    const [first, second, third] = result; // Destructure the result array
    const winMessageDiv = document.getElementById('win-message');
    if(first === second && second === third){
      winMessageDiv.innerHTML = 'Big Win'; // All three symbols match
    } else if(first === second || second === third || first === third){
      winMessageDiv.innerHTML = 'Small Win'; // Any two symbols match
    } else {
      winMessageDiv.innerHTML = 'No Win'; // No symbols match
    }
  };

  // Function to update the UI with the result
  const setResultOnUI = (result = []) => {
    const [first, second, third] = result; // Destructure the result array
    const firstImage = document.getElementById('first-image');
    const secondImage = document.getElementById('second-image');
    const thirdImage = document.getElementById('third-image');
    firstImage.src = `${ASSET_PATH}/Symbol_${first}.png`; // Set the source for the first image
    secondImage.src = `${ASSET_PATH}/Symbol_${second}.png`; // Set the source for the second image
    thirdImage.src = `${ASSET_PATH}/Symbol_${third}.png`; // Set the source for the third image
  };

  // Function to check and handle the bonus
  const checkBonus = (bonus) => {
    const retryBtn = document.getElementById('retry-button');
    if(!bonus){
      retryBtn.style['pointer-events']='auto'; // Enable retry button
      retryBtn.style.opacity = 1;
      return;
    }
    setMessage('You have a bonus !!'); // Display bonus message
    retryBtn.style['pointer-events']='none'; // Disable retry button
    retryBtn.style.opacity = 0.3;
    setTimeout(retryNewResult, 500); // Automatically retry after a delay
  };

  // Function to set a message in the UI
  const setMessage = (message) => {
    const messageDiv = document.getElementById('message');
    if(message){
      messageDiv.innerHTML = message; // Display the message
      messageDiv.style.opacity = 1;
    }else{
      messageDiv.style.opacity = 0; // Hide the message
    }
  };

  // Add event listener to the retry button to trigger a new result
  document.getElementById('retry-button').addEventListener('click', retryNewResult);
})();

```
This JavaScript file contains the client-side logic for the slot machine game. It might handle user interactions, animations, and game mechanics.

**app/style.css**
The CSS file defines the styling for the slot machine interface, including layout, colors, and fonts.

**server/handlers.js**
This file includes functions that handle HTTP requests. These functions are called by the routes defined in router.js.

**server/helpers.js**
Helper functions used across the server-side code are defined here. These might include utility functions for various tasks.

**server/router.js**
Defines the routing logic, mapping URL paths to handler functions in handlers.js.


![Slot Machine on Node.js Project Analysis](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/siw00u3tu8hjl66gpzlm.gif)

## Conclusion
The Slot Machine project is well-structured, with a clear separation between frontend and backend code. The use of configuration files like .eslintrc and package.json helps maintain code quality and manage dependencies effectively. The directory structure is logical and makes it easy to navigate the project.  

## Sources:
[1] - [https://github.com/a7ul/slot-machine](https://github.com/a7ul/slot-machine)