Add FSM

javascript/state.js

@@ -0,0 +1,23 @@
+var StateMachine = function(initial){
+  this.current = this.initial = initial;
+  this.scope = this;
+};
+
+(function(p){
+
+  p.states = {};
+  p.events = [];
+
+  p.changeState = function(stateName){
+    var next = this.states[stateName];
+    if (!next) return false;
+    var current = this.states[this.current];
+    current.onExit && current.onExit.call(this.scope, next);
+    next.onEnter && next.onEnter.call(this.scope, current);
+    this.current = stateName;
+    current.onExited && current.onExited.call(this.scope, next);
+    next.onEntered && next.onEntered.call(this.scope, current);
+    return this.current;
+  };
+
+})(StateMachine.prototype);