Sparkler is a macro‑based pattern‑matching engine for JavaScript that lets developers write native‑looking `function` and `match` clauses with literals, destructuring, guards, and custom extractors. It compiles via Sweet.js into plain `if`/`for` code with no runtime dependencies, providing optimized matching and optional extensions for built‑in types. The library is aimed at JavaScript developers who want functional‑style pattern matching and algebraic‑data‑type support without adding a heavy runtime.