Book Image

Practical WebAssembly

By : Sendil Kumar Nellaiyapen
Book Image

Practical WebAssembly

By: Sendil Kumar Nellaiyapen

Overview of this book

Rust is an open source language tuned toward safety, concurrency, and performance. WebAssembly brings all the capabilities of the native world into the JavaScript world. Together, Rust and WebAssembly provide a way to create robust and performant web applications. They help make your web applications blazingly fast and have small binaries. Developers working with JavaScript will be able to put their knowledge to work with this practical guide to developing faster and maintainable code. Complete with step-by-step explanations of essential concepts, examples, and self-assessment questions, you’ll begin by exploring WebAssembly, using the various tools provided by the ecosystem, and understanding how to use WebAssembly and JavaScript together to build a high-performing application. You’ll then learn binary code to work with a variety of tools that help you to convert native code into WebAssembly. The book will introduce you to the world of Rust and the ecosystem that makes it easy to build/ship WebAssembly-based applications. By the end of this WebAssembly Rust book, you’ll be able to create and ship your own WebAssembly applications using Rust and JavaScript, understand how to debug, and use the right tools to optimize and deliver high-performing applications.
Table of Contents (15 chapters)
1
Section 1: Introduction to WebAssembly
5
Section 2: WebAssembly Tools
9
Section 3: Rust and WebAssembly

Running Hello World with Emscripten in the browser

In this section, we will see how to convert C/C++ code into the WebAssembly binary via Emscripten and run it in the browser.

Note

If the terminal says that the emcc command is not found, it is highly likely that you have missed setting up the environment variables. To set up the environment variables, run the following command from inside the emsdk folder: source ./emsdk_env.sh

Let's use the same code example used in the Generating asm.js using Emscripten section . Now, instead of just running emcc, let's pass the -o option and instruct emcc to generate the .html file:

$ emcc hello_web.c -o helloweb.html

Once completed, the following files are generated:

  • helloweb.js
  • helloweb.wasm
  • helloweb.html

Similar to the Node example, the generated JavaScript file is huge. We will learn how to optimize the file size later in this chapter.

Note

The -o option ensures all the files generated...