fsm.js

JS State Machine

/**	
* Hairy Balls FSM	
*
*/	
	
var FSM = function(s, is) {	
    this.states = s;
    this.iState = is;
    this.curState = is;
}
	
	
FSM.prototype.update = function(agent) {	
  //Evaluate current state transition triggers
  var trans = this.states[this.curState]['Trans'];
  var newState = null;

  var actions = []; //Actions to perform
	
  for (var t in trans) {	
    if(trans[t].func(agent)) {
      newState = trans[t].transTo;
      actions.push(this.states[this.curState].exit);
      actions.push(this.states[newState].entry);
      break;
    }
  }	
  	
  if(newState) {	
    this.curState = newState; 
    
    //Trigger entry/exit actions	
    for (var f in actions) {
      actions[f](agent);
    }
    return;	
  }
	
  //No transitions triggered, run current state func	
  this.states[this.curState].func(agent);
}
	
	
var block = {	
  'Chillaxing' : {
    func: function(agent) {
      console.log('Just chillaxing'); 
    },	
    entry: function(agent) {
      console.log('Going to bed');
    }, 
    exit : function(agent) {
      console.log('Getting out of bed');
    },
    'Trans' : {
      'Rested -> Work' : {
         func : function(agent) {
           return agent.sleep > 5;
         },
         transTo : 'Working'
       }                     
     } 
  },
 'Working' : {	
    func : function(agent) {
      console.log("At work!");
    }, 
    entry : function(agent) {
      console.log("Going to work");
    }, 
    exit : function(agent){
      console.log("Leaving work");
    },
    'Trans' : {
      'Tired -> Chillaxing' : {
        func : function(agent) {
          return agent.sleep < 5;
        },
        transTo : 'Chillaxing'
       }  
    }
  } 	
}
	
var fsm = new FSM(block,'Chillaxing');
	
fsm.update({sleep:3});
fsm.update({sleep:10});	
fsm.update({sleep:10});
fsm.update({sleep:3});
fsm.update({sleep:3});