diff --git a/Observable.js b/Observable.js
index 03545cd..cf36710 100644
--- a/Observable.js
+++ b/Observable.js
@@ -11,12 +11,19 @@ class ObserverList {
   }
   add(observer) {
     // todo add observer to list
+    this.observerList.push(observer);
   }
   remove(observer) {
     // todo remove observer from list
+    let index=this.observerList.indexOf(observer);
+    if(index>-1){
+        this.observerList.splice(index,1);
+    }
+    
   }
   count() {
     // return observer list size
+    return this.observerList.length;
   }
 }
 
@@ -26,13 +33,20 @@ class Subject {
   }
   addObserver(observer) {
     // todo add observer
+    this.observers.add(observer);
   }
   removeObserver(observer) {
     // todo remove observer
+    this.observers.remove(observer);
   }
   notify(...args) {
     // todo notify
+    
+    var observerCount = this.observers.count();
+    for(var i=0; i < observerCount; i++){
+      this.observers.observerList[i].update(...args);
+    }
   }
 }
 
-module.exports = { Subject };
\ No newline at end of file
+module.exports = { Subject };
diff --git a/PubSub.js b/PubSub.js
index 0c7999e..b59fa37 100644
--- a/PubSub.js
+++ b/PubSub.js
@@ -13,14 +13,30 @@ module.exports = class PubSub {
 
   subscribe(type, fn) {
     // todo subscribe
+    if(!this.subscribers[type]){
+      this.subscribers[type]=[]; 
+    }
+    this.subscribers[type].push(fn);
+   
   }
 
   unsubscribe(type, fn) {
     // todo unsubscribe
+    if (!this.subscribers[type]) return;
+    const sub = this.subscribers[type];
+    const idx = sub.indexOf(fn);
+    if (idx >= 0) {
+      sub.splice(idx, 1);
+    }
   }
 
   publish(type, ...args) {
     // todo publish
+    const sub = this.subscribers[type];
+    if (!sub) return;
+    sub.forEach(fn => {
+      fn(...args);
+    })
   }
 
 }