MiniFSM: The Simple, Flexible TypeScript Library for Efficient Finite State Machine Implementation.
MiniFSM is a lightweight, flexible TypeScript library for implementing Finite State Machines (FSM) in both frontend and backend applications. Designed with simplicity in mind, it offers an intuitive way of managing state transitions in a highly descriptive manner.
Features
- Simple API: With just a few types and one core function, MiniFSM keeps things simple yet powerful.
- Backend and Frontend Compatibility: Versatile enough to be used across different development contexts.
- Immutability-Friendly: Designed to work well in immutable data environments, though not strictly enforced.
- Visualization Support: Easily visualize FSMs defined in MiniFSM for debugging and presentation.
Installation
Install MiniFSM using npm:
npm install minifsmOr using yarn:
yarn add minifsmUsage
Here's a basic example of how to use MiniFSM:
import {type FSMMachine, type FSMDefinition, doTransition, createNullTransition} from '@minifsm/core'
const STATES = {
GREEN: Symbol('green'),
YELLOW: Symbol('yellow'),
RED: Symbol('red'),
DISABLED: Symbol('disabled')
} as const
type TrafficLightState = typeof STATES[keyof typeof STATES]
interface TrafficLightContext {
turnOff: () => void,
lightRed: () => void,
lightYellow: () => void,
lightGreen: () => void,
}
type TrafficLightInput = { type: 'tick' }
function isTickCondition({ input }: { input: TrafficLightInput}): boolean {
return input.type === 'tick'
}
const trafficLightFSMDefinition: FSMDefinition<TrafficLightState, TrafficLightContext, TrafficLightInput> = {
[STATES.RED]: {
transitions: [
{
nextState: STATES.GREEN,
condition: isTickCondition,
action: ({ context }: {
context: TrafficLightContext
input: TrafficLightInput
}): TrafficLightContext => {
context.turnOff()
context.lightGreen()
return context
}
},
],
defaultTransition: createNullTransition(STATES.RED),
},
[STATES.YELLOW]: {
transitions: [
{
nextState: STATES.RED,
condition: isTickCondition,
action: ({ context }: {
context: TrafficLightContext
input: TrafficLightInput
}): TrafficLightContext => {
context.turnOff()
context.lightRed()
return context
}
},
],
defaultTransition: createNullTransition(STATES.YELLOW),
},
[STATES.GREEN]: {
transitions: [
{
nextState: STATES.YELLOW,
condition: isTickCondition,
action: ({ context }: {
context: TrafficLightContext
input: TrafficLightInput
}): TrafficLightContext => {
context.turnOff()
context.lightYellow()
return context
}
},
],
defaultTransition: createNullTransition(STATES.GREEN),
},
}
let machine: FSMMachine<TrafficLightState, TrafficLightContext> = {
currentState: STATES.RED,
context: {
turnOff: () => { console.clear() },
lightRed: () => { console.log('red') },
lightYellow: () => { console.log('yellow') },
lightGreen: () => { console.log('green') },
}
}
setInterval(() => {
machine = doTransition({ definition: trafficLightFSMDefinition, machine, input: { type: 'tick' }})
}, 1000)