diff --git a/Observable.js b/Observable.js
index 03545cd..dc0e201 100644
--- a/Observable.js
+++ b/Observable.js
@@ -10,13 +10,27 @@ class ObserverList {
     this.observerList = [];
   }
   add(observer) {
-    // todo add observer to list
+    this.observerList.push(observer);
   }
-  remove(observer) {
-    // todo remove observer from list
+  remove(index) {
+    this.observerList.splice(index, 1);
   }
   count() {
-    // return observer list size
+    return this.observerList.length;
+  }
+  get(index) {
+    return this.observerList[index];
+  }
+  indexOf(observer) {
+    let index = -1;
+
+    this.observerList.forEach((item, curIndex) => {
+      if (item === observer) {
+        index = curIndex;
+      }
+    });
+
+    return index;
   }
 }
 
@@ -25,13 +39,21 @@ class Subject {
     this.observers = new ObserverList();
   }
   addObserver(observer) {
-    // todo add observer
+    this.observers.add(observer);
   }
   removeObserver(observer) {
-    // todo remove observer
+    const index = this.observers.indexOf(observer);
+
+    this.observers.remove(index);
   }
   notify(...args) {
-    // todo notify
+    const len = this.observers.count();
+
+    for (let index = 0; index < len; index++) {
+      const observer = this.observers.get(index);
+      
+      observer.update(...args);
+    }
   }
 }
 
diff --git a/PubSub.js b/PubSub.js
index 0c7999e..9916f7a 100644
--- a/PubSub.js
+++ b/PubSub.js
@@ -9,18 +9,46 @@ module.exports = class PubSub {
 
   constructor() {
     this.subscribers = {};
+    this.id = 0;
   }
 
   subscribe(type, fn) {
-    // todo subscribe
+    if (!this.subscribe[type]) this.subscribe[type] = [];
+
+    this.subscribe[type].push({
+      token: this.id,
+      func: fn,
+    });
+
+    this.id += 1;
+
+    return this.id;
   }
 
   unsubscribe(type, fn) {
-    // todo unsubscribe
+    let subscribe = this.subscribe[type];
+
+    if (!subscribe) return false;
+
+    const len = subscribe.length;
+
+    subscribe.forEach((item, index) => {
+      if (item.func === fn) subscribe.splice(index, 1);
+    });
+
+    return this;
   }
 
   publish(type, ...args) {
-    // todo publish
+    const subscribe = this.subscribe[type];
+
+    if (!subscribe) return false;
+
+    subscribe.forEach((item) => {
+      item.func(args[0]);
+    });
+
+    return this;
   }
 
 }