Question 1

How do I pass a Rust struct to JavaScript using wasm-bindgen?

Accepted Answer

Use the #[wasm_bindgen] attribute on Rust structs to automatically generate JavaScript classes. For example, define a struct with methods, and wasm-bindgen will expose it with type-safe getters and setters. Check the guide for serialization details on complex types like vectors or enums.

Question 2

What's the difference between wasm-bindgen and js-sys?

Accepted Answer

wasm-bindgen is the core library for generating custom bindings between Rust and JavaScript. js-sys provides raw, low-level bindings to JavaScript's built-in objects like Array or Date, while wasm-bindgen offers higher-level abstractions. Typically, you use wasm-bindgen for application logic and js-sys when you need direct access to JavaScript APIs.

Question 3

Can I use wasm-bindgen with webpack or Vite?

Accepted Answer

Yes, wasm-bindgen integrates with modern bundlers. Compile Rust to WebAssembly, then use the generated JavaScript glue code in your project. The wasm-pack tool simplifies this by automating builds and outputting npm-compatible packages, as referenced in community resources.

Question 4

How to handle async JavaScript functions in Rust with wasm-bindgen?

Accepted Answer

Use the wasm-bindgen-futures crate to convert JavaScript Promises to Rust Futures. This allows you to await async calls like fetch() in Rust, making it easier to work with modern web APIs without blocking. Examples are in the API docs for seamless integration.

Question 5

Is wasm-bindgen good for server-side rendering with Node.js?

Accepted Answer

It can be used with Node.js, but support is less mature than for browsers. You might face issues with Node-specific modules or performance overhead. For SSR, consider if the benefits of WebAssembly outweigh the setup complexity compared to JavaScript frameworks.

Question 6

wasm-bindgen vs raw WebAssembly API: which is better?

Accepted Answer

wasm-bindgen abstracts low-level memory management and type conversions, offering type safety and reduced boilerplate. The raw WebAssembly JS API gives more control for hand-optimized performance but requires manual error handling. Choose wasm-bindgen for productivity and raw API for niche optimizations.

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