$ show ifandelse/machina.js
Machina.js is a TypeScript-first finite state machine library that provides both single-client and multi-client FSM implementations. It features hierarchical state machines with event bubbling, deferred input processing, lifecycle hooks, and a built-in event system. The library includes static analysis tools for detecting unreachable states and transition loops, testing utilities with custom matchers, React integration hooks, and an ESLint plugin for FSM validation. Built as a monorepo with pnpm and turbo, it emphasizes type safety and compile-time validation of state configurations.
The LLM identified 5 files worth highlighting for reuse:
A minimal but complete typed event emitter that provides compile-time validation of event names through TypeScript generics. It's isolated, reusable in any project, and demonstrates skill in creating a lightweight yet typesafe event system.
Serialization utilities that safely handle circular references, Date objects, Map/Set, and other complex types during dehydrate/rehydrate operations. This isolated component solves a common data persistence problem with non-obvious skill in handling edge cases.
A randomized input testing framework for state machines that uses deterministic seeds and invariant checking to verify FSM behavior. It demonstrates skill in creating reproducible property-based tests that can be extracted for use with other state-based systems.
Static analysis tool that extracts transition targets from handler functions by parsing various function syntaxes (arrow functions, method declarations, etc.). It shows non-obvious skill in AST traversal and pattern matching to determine possible state transitions.
React hooks that efficiently synchronize FSM state with React components using useSyncExternalStore. It demonstrates skill in bridging external state management with React's rendering lifecycle for optimal performance.