asyncmachine: A TypeScript repository from chansdad

AsyncMachine is a relational state machine made for declarative flow control. It supports multiple states simultaneously, executes methods based on a dependency graph and provides an event emitter.

It allows for easy:

state management
parallel tasks
loose coupling
resource allocation / disposal
exception handling
fault tolerance
method cancellation

It supports forming a network of state machines and can also be used as a simple state management library. Gzipped code is 7.5kb.

Install

npm i asyncmachine

Documentation

AsyncMachine - The Definitive Guide (wiki)
PDF version (25 pages, 1.5mb)
API docs (TypeScript)
Roadmap

Components:

Features:

Examples

Dry Wet

This basic examples makes use of: states, transitions, relations and synchronous mutations.

import { machine } from 'asyncmachine'
// define
const state = {
  // state Wet when activated, requires state Water to be active
  Wet: {
    require: ['Water']
  },
  // state Dry when activated, will drop (de-activate) state Wet
  Dry: {
    drop: ['Wet']
  },
  // state Water when activated, will add (activate) state Wet and
  // drop (de-activate) state Dry
  Water: {
    add: ['Wet'],
    drop: ['Dry']
  }
}
// initialize
const example = machine(state)
// initially the machine has no active states
example.is() // -> []
// activate state Dry
example.add('Dry')
example.is() // -> [ 'Dry' ]
// activate state Water, which will resolve the relations:
// 1. Water activates Wet
// 2. Wet requires Water
// 3. Dry de-activates Wet
// 4. Water de-activates Dry
// 5. Water activates Wet
example.add('Water')
example.is() // -> [ 'Wet', 'Water' ]

Negotiation

Presents how the state negotiation works.

Async Dialog

Presents the following concepts: automatic states, synchronous mutations, delayed mutations and loose coupling.

Exception State

A simple fault tolerance (retrying) using the Exception state.

Piping

Shows how pipes forward states between machines.

Transitions

Shows various types of transition handlers and the way params get passed to them.

TodoMVC and React

Classic TodoMCV example using AsyncMachine as the controller and React as the view.

State streams with RxJS

Observe state changes and navigate through specific paths with RxJS, then feed the result back as a state.

Comming soon!

Restaurant

A complex example showing how to solve the producer / consumer problem using AsyncMachine.

TaskBot

For a real world example check TaskBot - a real-time sync engine for Google APIs.

Use cases

state management
synchronizing async actions
solving non-linear problems
fault tolerance
resource allocation / disposal
avoiding race conditions
thread pools
sync engines

License

MIT

chansdad/asyncmachine