Rotifer v0.3: TypeScript WASM — Zero-Barrier Gene Authoring

Source: Dev.to

The biggest barrier to writing WASM genes was the toolchain. v0.3 removes it entirely: write a TypeScript function, run rotifer compile, and get a sandboxed WASM gene—zero configuration, no Rust or AssemblyScript required.

TS → WASM Pipeline

The new compilation pipeline chains three stages automatically:

TypeScript → esbuild (bundle) → WASI shim → Javy (QuickJS→WASM) → Rotifer IR

Compilation Commands

rotifer compile my-gene          # auto-detects index.ts, compiles to WASM
rotifer compile my-gene --lang ts  # force TypeScript mode

Under the Hood

Javy embeds QuickJS into a WASM module. The result is a fully sandboxed gene that runs in the same Wasmtime sandbox as hand‑written Rust genes, with identical fuel metering, memory limits, and security isolation.

WASI Sandbox Support

The Rust core’s WasmtimeSandbox now supports two execution modes:

• Direct – genes exporting an express function (original mode)
• WASI – genes using the _start entry point (Javy output)

A minimal WASI shim provides nine host functions (fd_read, fd_write, clock_time_get, etc.)—just enough for QuickJS to run, nothing more.

IR Verifier Updates

• SIMD instructions downgraded from error to warning (common in Javy/QuickJS output)
• _start entry point accepted alongside express for WASI modules

By the Numbers

• 180 → 275 tests (91 TypeScript + 184 Rust)
• Documentation updated across README (EN/ZH), Getting Started, and website

Get Started

npm install -g @rotifer/playground@alpha

Write a Gene

// genes/my-search/index.ts
export function express(input: { query: string }) {
  return { results: [`Found: ${input.query}`], total: 1 };
}

Compile and Submit

rotifer compile my-search
rotifer arena submit my-search

• Full Changelog

This article was originally published on rotifer.dev. Follow the project on GitLab or install the CLI: npm i -g @rotifer/playground.