What Emitter-FSM Does

This is a lightweight JavaScript library that lets you build a state machine—a system that moves between different states based on events. Instead of writing complex conditional logic scattered throughout your code, you define states upfront and the rules for moving between them. When something happens (an event), the system automatically transitions to the next state and notifies your code that the change occurred.

Think of it like a traffic light: it has three states (red, yellow, green), and it moves through them in a predictable sequence. Or a music player: it has states like "playing," "paused," and "stopped," and buttons trigger transitions between them. This library gives you a clean, organized way to model that behavior in your application.

Under the hood, it uses Node.js's EventEmitter—a built-in tool for triggering and listening to events. So when your state machine transitions, it broadcasts that event so other parts of your code can react to it. This keeps everything loosely coupled: your state machine doesn't need to know what listens to it, and listeners don't need to know the internal details of how states work.

You'd use this if you're building something with clear states and predictable transitions: a form wizard with step-by-step progression, a game with turn-based logic, an authentication flow (logging in, logged in, logged out), or any workflow where things need to happen in order. The README suggests checking the tests to learn how to use it—they show examples of how to set up states and define what transitions are allowed.

It's intentionally minimal and straightforward. There's no heavy framework overhead, just the core idea of state machines with event-driven notifications. That simplicity makes it easy to understand and drop into a project without a lot of setup.