WebAssembly in Action

Chapter 6. Creating a WebAssembly module that talks to JavaScript using function pointers

This chapter covers

• Adjusting C or C++ code to work with function pointers
• Using Emscripten’s helper functions to pass JavaScript functions to the WebAssembly module
• Calling function pointers in the WebAssembly module when not using Emscripten’s plumbing code

In chapter 5, you modified your module so that it was no longer passing a validation error message back to the JavaScript through a parameter. Instead, you modified the module so that it called a JavaScript function directly, as figure 6.1 illustrates.

Figure 6.1. The module calling a function in the JavaScript code

Imagine being able to pass a JavaScript function to the module based on your ...