Registry

• Writing Web Assembly
  • Code Splitting
  • Documentation
  • Logging

The registry class is written in C++ and exposed to WebAssembly using Emscripten. This choice was made to leverage the performance benefits of C++ for managing entities and components in an ECS architecture. Emscripten allows us to compile C++ code into WebAssembly, which can then be used in web applications, providing a bridge between high-performance C++ code and JavaScript.

Design Choices

This design makes some trade-offs between performance and ease of use. A pure C++ ECS would have been easier to use but having to bind it as us make choices that impact usability.

Const Correctness

In a regular C++ ECS, const correctness is a given, but when exposing C++ to WebAssembly, as in C++ we can force constant of return values. But in WebAssembly, the concept of const correctness does not directly translate to JavaScript. Therefore, methods that would typically return const references in C++ may return non-const references or copies when exposed to WebAssembly. We deciced to keep the const correctness in the C++ code to maintain clarity and intent within the C++ domain, even if it doesn’t fully carry over to the WebAssembly interface.

Error Handling

Any thrown exceptions in C++ will result in a runtime error in JavaScript. The problem with this approach is that the error messages may not be as descriptive or user-friendly as native JavaScript errors. As every error thrown in C++ will be caught as a generic runtime error in JavaScript, it can make debugging more challenging. To mitigate this, we recommend thorough testing and validation within the C++ code to catch potential issues before they propagate to the WebAssembly layer.