ts-fsm-fix
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    1.3.3 • Public • Published

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    🤖 Finite state machine written in typescript

    ❄️ ↔️ 🌊 ↔️ ♨️ Advanced control of entities' lifecycle.

    npm install ts-fsm
    yarn add ts-fsm

    Simple usage

    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, TRANSITION, IDATA>(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.

    new StateMachine<STATE, TRANSITION, IDATA>(
        STATE.SOLID, 
        states,
        transitions
    );
     
    new StateMachine<STATE, TRANSITION, IDATA>(
        STATE.SOLID, // initial state 
        {
            before: () => {}, // beforeEachState
            states,
            after: [() => {}, () => {}], // afterEachState
        }, {
            before: () => {}, // beforeEachTransition
            transitions,
            after: [() => {}, () => {}], // afterEachTransition
        }, {
            onError: () => {};
            timeout1000;
        }
    );

    🍃🎣 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
    const increaseEntropy = ({ transport }: { transport: IObject }) => {
        transport["entropy"] = transport["entropy"] === undefined ? 0 : transport["entropy"] + 1;
    };
     
    new StateMachine<STATE, TRANSITION, IDATA>(
        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.

    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.

    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.

    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.

    new StateMachine<STATE, TRANSITION, IDATA>(
        STATE.SOLID, 
        states,
        transitions,
        {
            onError(error) {
                someAwesomeLogger(error);
                makeSomeAction();
                throw CustomError("Custom Error!");
            }
        }
    ); 

    Install

    npm i ts-fsm-fix

    DownloadsWeekly Downloads

    2

    Version

    1.3.3

    License

    MIT

    Unpacked Size

    252 kB

    Total Files

    15

    Last publish

    Collaborators

    • ciekawy