Phase 1: WASM Compilation Infrastructure
- Add dual-target compilation support (C FFI + WASM) in Cargo.toml
- Make tokio/tokio-util optional, only for native builds
- Add WASM-specific dependencies (wasm-bindgen, js-sys, web-sys)
- Create build_wasm.sh script for WASM compilation
- Make baml-cli optional to exclude from WASM builds

Phase 2: Async Runtime Adaptation
- Create AsyncRuntime abstraction for platform-agnostic spawning
- Replace direct tokio::runtime usage with AsyncRuntime::spawn_local
- Add conditional compilation for libc types (c_char, c_int, c_void)
- Add WASM-bindgen exports for runtime creation and function calls
- Fix either crate imports for WASM compatibility

Both native and WASM targets now compile successfully:
- Native: cargo build --release
- WASM: cargo build --target wasm32-unknown-unknown --no-default-features --features wasm
- Generated WASM module size: ~11MB

Completed implementation of WASM FFI support for BAML runtime to enable
browser-based execution. This includes:

Phase 1: WASM Compilation Infrastructure
- Updated Cargo.toml with WASM target dependencies
- Created dual-target build system (native + WASM)
- Added build_wasm.sh script for WASM compilation

Phase 2: Async Runtime Adaptation
- Created platform-agnostic AsyncRuntime abstraction
- Replaced Tokio spawns with conditional compilation
- Implemented spawn_local for WASM compatibility

Phase 3: TypeScript Protobuf Layer
- Added TypeScript protobuf generation to build.rs
- Created buf.gen.yaml configuration
- Implemented encode.ts and decode.ts modeled after Go client
- Set up language_client_wasm package structure

Phase 4: WASM Runtime Client
- Implemented BamlWasmRuntime class with module loading
- Added WASM-specific exports to lib.rs
- Created promise-based function calling with callbacks
- Implemented streaming support

Current Status:
- WASM builds successfully (11MB)
- TypeScript compilation working
- Module exports configured
- Ready for Phase 5 browser testing

Known Issues:
- Protobuf serialization using JSON placeholder
- Callback mechanism needs completion
- WASM size needs optimization
- Browser testing pending

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <[email protected]>

- Add debug logging to async runtime spawn_local for WASM
- Add comprehensive debugging to FFI function calls
- Improve JavaScript callback invocation through window.__baml_callbacks
- Initialize baml_log directly in init_wasm for proper logging setup
- Add MIT license for language_client_cffi
- Fix callback data serialization to JavaScript arrays

- Update runtime.ts to handle global wasmModule and improve callback mechanism
- Add callbacks.js for JavaScript callback management utilities
- Add proto_utils.ts for protobuf serialization helpers
- Expand test.html with comprehensive test suite including memory management
- Add specialized test files for callback, debug, LLM, and simple scenarios
- Update implementation plan with Phase 5 completion and test results
- Document known limitations and production readiness checklist