fsm/dist/tests/00-basic.js

(() => {
  // src/index.ts
  var Machine = function(...states) {
    return { states };
  };
  var State = function(name, ...eventReactionCouplings) {
    return { name, eventReactionCouplings };
  };
  var On = function(eventName, ...reactions) {
    return { eventName, reactions };
  };
  var SideEffect = function(fn) {
    return { type: "SideEffect", fn };
  };
  var Goto = function(targetStateName) {
    return { type: "Goto", targetStateName };
  };
  function interpret(machine2, options) {
    let { state, context } = options;
    if (typeof state === "undefined") {
      state = machine2.states[0].name;
    }
    const interpreter = { machine: machine2, state, context, eventQueue: [], isTransitioning: false };
    send(interpreter, ["entry", null]);
    return interpreter;
  }
  function getState(interpreter) {
    return interpreter.machine.states.find((state) => state.name === interpreter.state);
  }
  function getMatchingEventReactionCouplings(state, event) {
    return state.eventReactionCouplings.filter((eventReactionCoupling) => eventReactionCoupling.eventName === event[0]);
  }
  function send(interpreter, event) {
    interpreter.eventQueue.push(event);
    if (interpreter.isTransitioning === false) {
      interpreter.isTransitioning = true;
      while (interpreter.eventQueue.length > 0) {
        processNextEvent(interpreter);
      }
      interpreter.isTransitioning = false;
    }
  }
  function processNextEvent(interpreter) {
    const nextEvent = interpreter.eventQueue.shift();
    if (typeof nextEvent !== "undefined") {
      const state = getState(interpreter);
      const eventReactionCouplings = getMatchingEventReactionCouplings(state, nextEvent);
      const reactions = eventReactionCouplings.map((eventReactionCoupling) => eventReactionCoupling.reactions).flat();
      const { sideEffects, contextMutations, goto_ } = categorizeReactions(reactions);
      sideEffects.forEach((sideEffect) => {
        sideEffect.fn(interpreter.context, nextEvent, interpreter);
      });
      contextMutations.forEach((contextMutation) => {
        interpreter.context = contextMutation.fn(interpreter.context, nextEvent, interpreter);
      });
      if (goto_ !== null) {
        interpreter.state = goto_.targetStateName;
        send(interpreter, ["entry", null]);
      }
    }
  }
  function categorizeReactions(reactions) {
    let sideEffects = [], contextMutations = [], goto_ = null;
    reactions.forEach((reaction) => {
      if (reaction.type === "SideEffect") {
        sideEffects.push(reaction);
      } else if (reaction.type === "ContextMutation") {
        contextMutations.push(reaction);
      } else if (reaction.type === "Goto") {
        goto_ = reaction;
      }
    });
    return { sideEffects, contextMutations, goto_ };
  }

  // src/tests/00-basic.ts
  var beginTimer = (ctx, e, self) => {
    setTimeout(() => {
      send(self, ["timer-finished", null]);
    }, 800);
  };
  var log = (ctx, e, self) => {
    console.log(self.state);
  };
  var machine = Machine(
    State(
      "green",
      On(
        "entry",
        SideEffect(beginTimer),
        SideEffect(log)
      ),
      On(
        "timer-finished",
        Goto("yellow")
      )
    ),
    State(
      "yellow",
      On(
        "entry",
        SideEffect(beginTimer),
        SideEffect(log)
      ),
      On(
        "timer-finished",
        Goto("red")
      )
    ),
    State(
      "red",
      On(
        "entry",
        SideEffect(beginTimer),
        SideEffect(log)
      ),
      On(
        "timer-finished",
        Goto("green")
      )
    )
  );
  var actor = interpret(machine, { context: {} });
})();