fsm-light

A lightweight, easy-to-use finite state machine (FSM) for managing entity status transitions in JavaScript/TypeScript projects.

Table of Contents

• Introduction
• Features
• Installation
• Usage
• License

Introduction

fsm-light is a simple, lightweight library for implementing finite state machines in JavaScript or TypeScript. It helps you define the possible transitions of an entity between states (statuses) in a clean, declarative way. You can easily check whether a transition can be performed and then execute that transition.

Features

• Lightweight: Minimal overhead, easy to integrate.
• TypeScript Support: Includes type definitions.
• Declarative Transitions: Clearly define from and to states for each action.
• Readable and Maintainable: Centralized state transition logic.
• CJM, ESM support: Supports both CommonJS and ES modules.

Installation

npm install fsm-light

Or with Yarn:

yarn add fsm-light

Usage

Import StateMachine:

import StateMachine from 'fsm-light';

Create a new instance of StateMachine by providing a definition object:

const userFsm = new StateMachine({
  initial: 'invited',
  transitions: {
    activate: { from: ['blocked', 'archived'], to: 'active' },
    archive:  { from: ['active'],              to: 'archived' },
    block:    { from: ['active', 'archived'],  to: 'blocked' },
    signUp:   { from: ['invited'],             to: 'active' }
  }
});

Create an entity and transition its status:

(The entity has to respond to status!!!)

const user = new User({
  firstName: 'John',
  lastName: 'Doe',
  email: '[email protected]',
  status: 'active'
});

user.status // 'active'
userFsm.can(user, 'archive') // true
userFsm.can(user, 'activate') // false
userFsm.transit(user, 'archive')
user.status // 'archived'

License

This project is licensed under the MIT License.

Package URL

https://www.npmjs.com/package/fsm-light

Code repository

https://bitbucket.org/endeavia/fsm-light/src/master/

Author

Tamás Kamarás