# ts-fsm-fix > Finite state machine written in typescript Latest version **1.3.3** (published 2019-08-26) · MIT license · 0 weekly downloads ## Install ```sh npm install ts-fsm-fix pnpm add ts-fsm-fix yarn add ts-fsm-fix bun add ts-fsm-fix ``` ## Health **Score 30/100 (F)** — status: abandoned. Positive: has types; esm support; no vulnerabilities; high quality score. Warnings: low downloads. Negative: abandoned; low maintenance score. ## Facts | | | |---|---| | Version | 1.3.3 | | Published | 2019-08-26 | | First published | 2019-08-26 | | Weekly downloads | 0 | | License | MIT | | TypeScript types | bundled | | Module format | ESM + CommonJS | | Node | >=6.0.0 | | Dependencies | 1 | | Unpacked size | 245.8 KB | | Known vulnerabilities | 0 | | Install scripts | no | | GitHub stars | 22 | | Author | khraks-mamtsov | | Maintainers | ciekawy | | Keywords | typescript, state-machine, state-management, lifecycle | ## Links - npm: https://www.npmjs.com/package/ts-fsm-fix - Repository: https://github.com/KhraksMamtsov/ts-fsm - Homepage: https://github.com/KhraksMamtsov/ts-fsm#readme - Issues: https://github.com/KhraksMamtsov/ts-fsm/issues - npm.io page: https://npm.io/package/ts-fsm-fix ## Dependencies (1) - [reflect-metadata](https://npm.io/package/reflect-metadata.md) ^0.1.12 ## Alternatives - [@reckona/mreact-store](https://npm.io/package/@reckona/mreact-store.md) — 976 weekly downloads - [regular-state](https://npm.io/package/regular-state.md) — 410 weekly downloads - [@pacote/flux-actions](https://npm.io/package/@pacote/flux-actions.md) — 65 weekly downloads - [@pilotlab/lux-debug](https://npm.io/package/@pilotlab/lux-debug.md) — 39 weekly downloads - [vue-persist-state](https://npm.io/package/vue-persist-state.md) — 19 weekly downloads ## Recent versions - 1.3.3 (latest) — 2019-08-26 ## README ![GitHub top language](https://img.shields.io/github/languages/top/KhraksMamtsov/ts-fsm.svg?style=flat-square) ![npm type definitions](https://img.shields.io/npm/types/ts-fsm.svg?style=flat-square) [![Build Status](https://img.shields.io/travis/KhraksMamtsov/ts-fsm/master.svg?style=flat-square)](https://travis-ci.org/KhraksMamtsov/ts-fsm) [![Coverage Status](https://img.shields.io/coveralls/github/KhraksMamtsov/ts-fsm/master.svg?style=flat-square)](https://coveralls.io/github/KhraksMamtsov/ts-fsm?branch=master) [![npm bundle size (minified + gzip)](https://img.shields.io/bundlephobia/minzip/ts-fsm.svg?style=flat-square)](https://bundlephobia.com/result?p=ts-fsm) [![npm bundle size (minified)](https://img.shields.io/bundlephobia/min/ts-fsm.svg?style=flat-square)](https://bundlephobia.com/result?p=ts-fsm) ![license](https://img.shields.io/github/license/KhraksMamtsov/ts-fsm.svg?style=flat-square) # 🤖 Finite state machine written in typescript ❄️ ↔️ 🌊 ↔️ ♨️ Advanced control of entities' lifecycle. ```cmd npm install ts-fsm yarn add ts-fsm ``` ## Simple usage ```typescript import StateMachine from "ts-fsm"; enum STATE { SOLID = "SOLID", LIQUID = "LIQUID", GAS = "GAS", } enum TRANSITION { MELT = "MELT", VAPORIZE = "VAPORIZE", CONDENSE = "CONDENSE", FREEZE = "FREEZE", } interface IDATA { temperature: number; } const states = [{ name: STATE.SOLID, data: { temperature: -100 }, }, { name: STATE.LIQUID, data: { temperature: 50 }, }, { name: STATE.GAS, data: { temperature: 200 }, }]; const transitions = [{ name: TRANSITION.MELT, from: STATE.SOLID, to: STATE.LIQUID, }, { name: TRANSITION.FREEZE, from: STATE.LIQUID, to: STATE.SOLID, }, { name: TRANSITION.VAPORIZE, from: STATE.LIQUID, to: STATE.GAS, }, { name: TRANSITION.CONDENSE, from: STATE.GAS, to: STATE.LIQUID, }]; const sm = new StateMachine(STATE.SOLID, states, transitions); sm.state // "SOLID" sm.data // { temperature: -100 } sm.transitTo(STATE.LIQUID) // Promise { sm } .then(sm => { sm.state; // "LIQUID" sm.data; // { temperature: 50 } }); sm.doTransition(TRANSITION.VAPORIZE) // Promise { sm } .then(sm => { sm.state; // "GAS" sm.data; // { temperature: 200 } }); ``` ## 🏁🏁 Initialization `ts-fsm` provide overloaded constructor and methods signature. ```typescript new StateMachine( STATE.SOLID, states, transitions ); new StateMachine( STATE.SOLID, // initial state { before: () => {}, // beforeEachState states, after: [() => {}, () => {}], // afterEachState }, { before: () => {}, // beforeEachTransition transitions, after: [() => {}, () => {}], // afterEachTransition }, { onError: () => {}; timeout: 1000; } ); ``` ## 🍃🎣 Lifecycle Hooks State machine provide several hooks for track or perform an action when a transition occurs. As a handler, both a single function and an array of functions can be passed. As a value, the handler takes `transport`, `from-state`, `to-state`. `this` - an instance of state machine. `transport` argument - mutable object, shared and passed through each hook handler. Transition can be canceled from any handler with explicitly return `false` or `Promise { false }`, in this case, then the subsequent handlers are not called, and state machine return to previous state. Each handler can be limited by time with passing `timeout` setting into constructor. | Hook | Define | Fired | |------|--------|-------| | ```afterEachState``` | constructor: state: after | after any state | ```afterState``` | state: after | after specific state | ```beforeEachTransition``` | constructor: transition: before | before any transition | ```beforeTransition``` | transition: before | before specific transition |-|-|-| | ```afterTransition``` | transition: after | after specific transition | ```afterEachTransition``` | constructor: transition: after | after any transition | ```beforeState``` | state: before | before specific state | ```beforeEachState``` | constructor: state: before | before any state ```typescript const increaseEntropy = ({ transport }: { transport: IObject }) => { transport["entropy"] = transport["entropy"] === undefined ? 0 : transport["entropy"] + 1; }; new StateMachine( STATE.SOLID, { before: increaseEntropy, // accept single function or array of functions states, after: [ // accept single function or array of functions (transport, from, to) => { console.log(transport["entropy"]); // 0 }, increaseEntropy, (transport, from, to) => { console.log(transport["entropy"]); // 1 }, ] }, transitions ); ``` Also additional aruments can be passed to `transitTo` and `doTransition` methods. ```typescript const handler = (transport, from, to, ...args) => { console.log(args); } sm.transitTo(STATE.GAS, 1, null, "3"); // [1, null, "3"] ``` ## ⏲️⏲️ Pending state `doTransition` and `transitTo` methods set state machine into pending state. ```typescript sm.isPending; // false sm.transitTo(STATE.GAS) .then(sm => { sm.isPending; // false }); sm.isPending; // true sm.transitTo(STATE.LIQUID) // throws: StateMachineError#PENDING_STATE ``` ## 🏜️🌧️ Hydration \ dehydration Hydration\dehydration mechanism allows save\recover current state of state machine. Getter `dehydrated` returns simple plain object-representation of state machine's state. Method `hydrate` accept object returned by `dehydrated` and recover state. ```typescript const currentState = sm.hydrated; console.log(currentState); /* { state: "GAS", data: { temperature: 200 }, transport: { entropy: 2 } } */ saveToAnywhere(currentState); // *********** // later const savedState = getFromAnywhere(); sm.hydrate(savedState); ``` ## 🚫⚠️ Custom error handling By default `ts-fsm` throw errors, but this behaviour mey be changed with `onError` handler function implementation. Each time, then `ts-fsm` throw an error firstly will fire `onError` handler with error passed with first argument. `onError` may throw it's custom error, otherwise `ts-fsm`'s error will thrown. Anyway state machine throw error. ```typescript new StateMachine( STATE.SOLID, states, transitions, { onError(error) { someAwesomeLogger(error); makeSomeAction(); throw CustomError("Custom Error!"); } } ); ``` --- _Source: https://npm.io/package/ts-fsm-fix · Machine-readable twin of the npm.io package page. Health data is recomputed on every publish._