Before we start and dive into the content, let's take a quick look at how this course works, because it's not your typical online course and it will help you make the most out of it. Here's what makes the approach of Learn WebAssembly unique:
Interactive Learning: Every concept is accompanied by hands-on exercises. You'll write and run WebAssembly code right in your browser.
Real-time Feedback: The course features a custom-built virtual machine and debugger explicitly tailored to this course, providing immediate visualization of your code. This interactive environment lets you observe stack changes, memory updates, and execution flow, enhancing your understanding of complex WebAssembly concepts without relying on external tools or browser DevTools.
Practical Exercises: You'll work on coding exercises and small projects that demonstrate WebAssembly concepts, giving you hands-on experience with WebAssembly. While these may not be full-scale real-world applications, they are designed to illustrate key principles and techniques used in WebAssembly development.
Comprehensive Coverage of Fundamentals: From basic concepts to core WebAssembly features, this course covers significant ground in WebAssembly fundamentals. By the end, you'll have a thorough understanding of the essential concepts of WebAssembly and how to use them.
Flexible Learning: While the course is structured, feel free to jump to sections that interest you most. Each chapter builds on the previous ones, but you're in control of your learning journey.
The unique approach of Learn WebAssembly is designed to maximize your learning experience. By providing practical exercises, this course aims to make your journey into WebAssembly engaging and effective. The goal is not just to teach you the concepts, but to help you truly understand and apply them.
To provide you with the best possible learning experience, this course features a custom learning environment specifically designed for mastering WebAssembly. The environment combines an interactive code editor, a WebAssembly virtual machine, and a powerful debugger that lets you visualize and understand exactly what's happening as your code executes. You'll be able to write WebAssembly code, see how the stack and memory change in real-time, and gain deep insights into how WebAssembly works under the hood. This interactive approach makes learning WebAssembly much more engaging and helps make the concepts stick.
So, how does it work?
What you can see here, is pretty much the interactive learning environment. This is what you'll see when you're working on a lesson that contains practical exercises.
Your screen is divided into two main areas. On the left, you'll find the lesson content, explanations, and guidance for each topic. On the right is where the magic happens: the custom-built workbench where you'll write, run, and debug WebAssembly code.
The workbench is more than just a code editor – it's a complete WebAssembly development environment built from scratch specifically for this course. You can see exactly what's happening inside your WebAssembly module.
The debugger provides a clear view into how your code executes. You can step through your code line by line, watching in real-time as values move on and off the stack, inspect the contents of memory, and understand exactly how your WebAssembly module operates. This immediate feedback makes it much easier to grasp WebAssembly's core concepts and will really help you understand how it works under the hood.
It also features a console that lets you see the output of your code and, for example, interactively call functions.
Throughout the course, you'll see code blocks that guide you through exercises. Green highlights show code you should add, while red indicates code to remove. This visual approach makes it clear exactly what changes to make as you progress through each lesson.
Let's try a simple example to see how it all works.
As we can see, main.wat contains a simple WebAssembly module with a single function add that takes two parameters, adds them together, and returns the result. We also have an index.js file that contains JavaScript code that will run the WebAssembly module and print the result to the console. Don't worry if you don't understand the syntax yet, we'll cover all of that in this course!
Now, you can either click on the Run button in the top right corner or press CTRL + Enter, or ⌘ + Enter on macOS to compile and run the code.
When you run the code, it will compile and execute it. The debugger will automatically pause at the beginning of the function, allowing you to step through the code and see exactly what happens when the code runs.
I encourage you to step through the code to get a feel for how it works. You can click on the Step Over button, which will execute the current line and move to the next one. Repeat this a few times to reach the end of the function or click on the Continue button to let the code immediately run until the end. Once you've reached the end of the function, the console will pop up and show you the output.
Throughout this course, we'll debug increasingly complex code and explore all the powerful features of the debugger in detail, such as the stack, tracking variables, inspecting memory, and more. These debugging tools will be invaluable as you progress through more advanced WebAssembly concepts and will help you understand exactly how your code works.
Now, let's try to change the code.
(module
(func $add (export "add") (param $a i32) (param $b i32) (result i32)
local.get $a
local.get $b
i32.add
)
(func $subtract (export "subtract") (param $a i32) (param $b i32) (result i32)
local.get $a
local.get $b
i32.sub
)
)We removed the add function and added a subtract function that takes two parameters, subtracts the second from the first, and returns the result.
We'll also need to update the index.js file to use the new subtract function:
const { instance, module } = await WebAssembly.instantiate(bytes);
const { add subtract } = instance.exports;
console.log(add(1, 2));
console.log(subtract(2, 1));Let's run the code again! This time the console will output 1 instead of 3.
While the course follows a structured path through WebAssembly concepts, you're in control of your learning journey. The exercises have been thoughtfully chosen to build on each other as you progress through the course. Each lesson builds on previous knowledge, but you're free to explore topics at your own pace.
The interactive learning environment allows you to experiment with code, modify it, and see the results instantly.
Tell me and I forget, teach me and I may remember, involve me and I learn. - Benjamin Franklin
Remember that learning WebAssembly is a process, and making mistakes is part of that process. When you encounter challenges, use the debugger to understand what's happening. Watch the stack, inspect memory, and step through your code. These tools will help you throughout the entire course.
While learning WebAssembly, it's normal to encounter challenges. Here are some strategies to help you when you're stuck:
Use the Debugger: Step through your code line by line to understand what's happening. Watch how values move on the stack and how memory changes.
Review Previous Lessons: Often, the solution involves concepts from earlier sections. Take a quick look back if needed.
Experiment: Try modifying the code slightly and observe the results. This can help build understanding of how different parts work.
Check the Console: Error messages can provide valuable hints about what's wrong.
Take a Break: Sometimes stepping away for a few minutes helps you see the problem with fresh eyes.
If you've tried these approaches and are still stuck:
Remember that the Show Solution button should be used as a last resort. The learning experience is most effective when you work through challenges on your own, even if it takes more time.
With that, are you ready to dive in? Let's start your journey to becoming a WebAssembly expert! 🚀