State Machine Implimentation

stateMachine.js

// state machine
var stm = {
  'stateA': {
    events: {
      'ev1': function(){
        this.state = 'stateB';
        // a certain action
      },
      'ev2': function(){
        this.state = 'stateC';
        // a certain action
      }
    }
  },
  'stateB': {
    events: {
      'ev3': function(){
        this.state = 'stateC';
        // a certain action
      }
    }
  },
  'stateC': {
    enter: function(){
      // a certain action
    },
    leave: function(){
      // a certain action
    },
    events: {
      'ev1': function(){
        // a certain action
      }
    }
  }
}

(function(player){
  var state = player.state;
  var noop = function() {};
  (stm[state].events[player.eventType] || noop).apply(player)

  if (state !== player.state) {
    (stm[state].leave || noop).apply(player);
    (stm[player.state].enter || noop).apply(player);
  }
})(player)