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)
Section 1: Introduction to WebAssembly
Section 2: WebAssembly Tools
Section 3: Rust and WebAssembly

Exports and imports

A WebAssembly module consists of export and import sections. These sections are responsible for exporting functions out of and importing functions into the WebAssembly module.


In order to call the functions defined in a WebAssembly module from JavaScript, we need to export the functions from the WebAssembly module. The export section is where we will define all the functions that are exported out of the WebAssembly module.

Let's go back to our classic add.wat example from the previous chapter:

; add.wat
    (func $add (param $lhs i32) (param $rhs i32) 
      (result i32)
        get_local $lhs
        get_local $rhs
    (export "add" (func $add))

Here, we have exported the add function using the (export "add...