Have you always wanted to become a JavaScript game developer, but weren‘t sure where to start? Well, you clicked the right article!
In this comprehensive guide, I‘ll teach you how to code the classic snake game from scratch step-by-step. Along the way, you‘ll master core programming concepts like variables, loops, conditionals and more.
Even if you‘ve never written a single line of code before, you can create your own playable snake game using just HTML, CSS and JavaScript. How cool is that!
Here‘s what we‘ll cover:
- Setting up the project files
- Drawing dynamic elements on canvas
- Animating the snake to slither around
- Generating yummy snacks for it to munch
- Adding logics for game over states
- Responding to arrow keys to twist and turn
- Putting it all together with a game loop
I‘ll explain each section clearly with detailed code snippets and visuals.
By the end, you‘ll advance from coding newbie to JavaScript game developer!
Let‘s get started…
Why Learn Game Development with JavaScript?
Before we dive into Snake specifically, you might wonder – why choose JavaScript for game coding in the first place?
Well, here are some key reasons:
- Accessibility – You only need a browser and text editor to get started
- Transferability – Concepts carry over into other programming languages
- Employability – Games teach widely applicable coding skills
- Sharability – You can easily share web games; just send a link!
JavaScript games also represent a massive chunk of development activity today:
With over 217,000 gaming repositories on GitHub, it‘s clear JavaScript is a popular choice for writing games.
And the global gaming market keeps expanding rapidly:
So by mastering these skills as a developer, you can access a $203 billion dollar industry!
Now that you know why JavaScript games are worth learning, let‘s explore how by coding Snake.
Our end goal is to publish a fun, playable game like this:
Ready to get coding? Then let‘s set up our project…
Setting Up the Project Files
All we need get started are these core files:
- index.html – Provides the HTML structure
- styles.css – Handles visual styling
- snake.js – Contains the JavaScript game code
Here‘s how our index.html looks initially:
This sets up the canvas element that acts as our game area, links our CSS and JavaScript, and adds a hidden "Game Over" screen we can toggle later.
The styles.css centers aligns that game canvas on screen:
Now we have a blank webpage with a ready-to-go 400×400 pixel canvas.
Let‘s switch over to snake.js where we‘ll handle…
Drawing and Animating Elements on Canvas
The first step is preparing our canvas context and defining some sizing constants:
gridSize controls the full width/height for gameplay. unitLength splits that into smaller 10-pixel blocks.
We can visualize this grid system:
Next up, we initialize the snake body and positions:
By looping from tail to head storing x/y coordinates, we can draw snake segments onto the canvas.
Together with borders, it looks like:
To animate movement, we:
- Copy current head position
- Offset x/y based on direction
- Add new head and remove old tail
This smooths slides the snake around grid, leaving it the same length.
So with just a few variables, functions and conditionals we can render and animate game objects!
Now for something more dynamic…
Generating Random Food Drops
What fun is a snake game if our reptile friend has nothing nibble on?
Let‘s randomly spawn snack spots. But first, a check – we don‘t want food overlapping snake parts.
With collision detection coded, food generation is straightforward:
The key steps:
- Randomly pick x and y values
- Validate no snake collisions
- Save coordinates as the food position
- Draw on canvas
Yummy! But constantly adding snacks eventually fills up space.
To counter that, we need to handle…
Game Over States and Conditions
No game is complete without a losing state! Let‘s code one up…
First, collision checks for the walls:
And again for head-body impacts:
If either case hits, game over!
We also handle edge cases like filling the whole grid:
By limiting food generation attempts, eventual overflow triggers a loss.
Finally, game over screens:
Here we toggle visibility when a collision flag gets raised.
With outcomes coded, let‘s work on controls so players can actually move…
Capturing Arrow Key Presses for Input
What‘s the point in masterfully coding snake navigation if we can‘t control the slippery reptile?
Let‘s capture keyboard button presses:
Based on which arrow key, we pass movement directions to our snake engine.
This allows dynamic user control as we slither along. Nice!
But modern games involve continuous motion – we need a…
Game Loop to Animate the Action
At the core of all animated games lies an infinite loop, running every fraction of a second to:
- Move elements
- Check for states like collisions
- Render updated graphics
By calling a single gameLoop() function, our snake comes alive:
Wrapped in a loop, our snake can wriggle forever…or at least until it crashes!
Troubleshooting Tips for New Coders
While coding your own snake.js file, some common beginner gotchas include:
Block Flickering – Double buffer by drawing next snake position before removing old tail to prevent blinking.
Button Mashing – Limit direction changes to stop players making illegal reverse turns.
Slow Performance – Use requestAnimationFrame over setInterval for faster redraws.
Stuck on a specific coding challenge? Check your solution against the completed example project on GitHub.
As a general debug tip – log key variable values throughout execution. Spot where they divert from expected state.
With some targeted troubleshooting, you‘ll get that snake slithering smoothly in no time!
Key Takeaways from this JavaScript Tutorial
If you made it this far…congratulations!!
You just leveraged core programming concepts like:
- Variables and constants
- Functions and parameters
- Conditional logic
- Datatypes like arrays and objects
- Loops and iteration
- Event handling
These skills apply to all kinds of JavaScript projects – web, mobile, data science, DevOps automation and more!
You also built a super impressive snake game from absolute scratch!
To recap, we:
- Set up project file structure
- Created canvas elements
- Coded snake movement logic
- Generated random food drops
- Handled game over conditions
- Captured arrow key input
- Animate everything with a game loop
Not bad for a day‘s work!
Want to level up even more as a JavaScript dev? Here are some related intermediate tutorials:
- Build an Image Carousel Slider
- Create a Countdown Timer
- Connect to a Data API with Fetch
- Build a Mini Map App from Scratch
The world of JavaScript is your oyster!
I hope you enjoyed this friendly coding tutorial for beginners. Now grab a laptop and start building something awesome!
Let me know if you have any other questions. And if you create a fun JavaScript game based on this guide, share your projects below!
Happy coding! :snake:
