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WASM Target

Compile Noether's Pure Rust stdlib stages to WebAssembly for zero-latency in-browser execution.

Status

noether build --target browser is implemented and produces a self-contained HTML bundle. The compiler emits a JavaScript reactive runtime that wires stage outputs to DOM nodes. Pure stages execute in-process (no network round-trips).

See noether build CLI reference for flags and output options.

What gets compiled to WASM

Only InlineExecutor-backed stages (the Pure Rust stdlib) are compiled to WASM. These are all deterministic, have no side effects, and benefit the most from in-process execution.

Stages that require NixExecutor (Python/Bash code) are not included in the WASM bundle — they require a subprocess and cannot run in a browser sandbox.

Stage kind WASM bundle Notes
Pure Rust stdlib ✅ Included InlineExecutor, zero overhead
Python / Bash (Nix) ❌ Excluded Requires subprocess
LLM stages ❌ Excluded Require network
Composition graphs mixing both Partial Pure subgraphs compiled; Nix stages need a backend

Architecture

noether build graph.json --target browser --output ./dist/app.html
        │
        ├── Type-check graph (same as regular run)
        ├── Walk graph; emit JS module per Pure stage
        ├── Compile Rust stdlib to WASM (wasm32-unknown-unknown)
        ├── Emit reactive JS runtime (signals-based)
        └── Bundle into single-file HTML (inline WASM + JS)

The emitted HTML is self-contained — no server needed, no CDN dependencies.

Limitations

  • Hot paths only: mixing Pure WASM stages with NixExecutor stages in the same composition requires a backend proxy for the Nix stages.
  • WASM binary size: the full Pure stdlib compiles to ~400 KB (Brotli-compressed).
  • Streaming types (Stream<T>) are not yet supported in the WASM runtime.

See also