Revenant

A CLI that scaffolds and drives Rust/WebAssembly + SvelteKit projects. Write logic in Rust, compile to WASM, and consume it from Svelte 5 — one tool manages the entire build loop, including a generated TypeScript facade that hides the raw wasm-bindgen package.

Why

Setting up Rust/WASM with SvelteKit by hand means wiring together wasm-pack, Vite plugins, path aliases, and a file watcher — then hoping they stay in sync. wasm-pack has no --watch flag (wasm-pack#457), so you either poll manually or write your own watcher. Revenant does this once, correctly, so you can focus on code.

Requirements

• Rust (with cargo) — rustup.rs
• Node.js 18+ (with npm) — nodejs.org
• wasm-pack — auto-installed via cargo install wasm-pack if missing

Not sure what you have? Run revenant setup for a guided checklist.

Quick Start

cargo install --path .

revenant new my-app
cd my-app
revenant dev

Open the URL printed by the dev server. You should see "Hello from my-app, World!" rendered by the Svelte page calling your Rust WASM function.

Commands

revenant new <name>

Scaffolds a complete project: Rust WASM crate, SvelteKit app, Vite config with WASM plugins, and a working hello-world example. Runs npm install automatically.

revenant dev

Runs an initial WASM build, starts a file watcher on rust/src/, and launches the SvelteKit dev server. Rust changes trigger automatic WASM rebuilds plus regeneration of web/src/lib/wasm.ts and pkg/revenant.contract.json. Ctrl+C cleanly stops all processes.

revenant build

Production build: wasm-pack build --release followed by npm run build. Before the web build, Revenant regenerates the typed Svelte facade from the Rust exports. Fails fast if either step errors.

revenant setup

Interactive checklist that verifies each required tool is installed and provides OS-specific installation instructions for anything missing.

--verbose

All commands accept --verbose to show full child process output (wasm-pack, npm). Without it, output is kept clean and errors include relevant details.

Project Structure

my-app/
├── revenant.toml         # project config (name, wasm target, package manager)
├── GETTING_STARTED.md    # tutorial: adding functions, calling from Svelte
├── rust/                 # wasm-pack crate
│   ├── Cargo.toml
│   └── src/lib.rs        # your Rust code — #[wasm_bindgen] exports
└── web/                  # SvelteKit app
    ├── package.json
    ├── svelte.config.js
    ├── vite.config.js    # wasm plugin + path alias to pkg/
    └── src/
        ├── app.html
        ├── lib/wasm.ts   # generated typed facade; import this, not pkg/
        └── routes/
            └── +page.svelte  # imports from $lib/wasm

WASM output goes to pkg/ at the project root, alongside pkg/revenant.contract.json — the intermediate contract manifest Revenant derives from rust/src/lib.rs. vite-plugin-wasm and vite-plugin-top-level-await handle browser-side loading.

Roadmap

v2 — Vite plugin that triggers wasm-pack on import resolution, replacing the custom file watcher. Also: WASI target support, pnpm/yarn/bun as package manager options, scaffold template variants.

v3 — Post-build transform pipeline (wasm-opt, size reporting, custom codegen) as a trait-based extension point.