From 9208479e81a8605b8dfbf1aef95d3c18b9c17122 Mon Sep 17 00:00:00 2001
From: ocean010101 <yangyang01.xu@outlook.com>
Date: Wed, 27 Mar 2019 06:52:58 +0800
Subject: [PATCH] completet exercise17.

Signed-off-by: ocean010101 <yangyang01.xu@outlook.com>
---
 Observable.js | 15 +++++++++++++++
 PubSub.js     | 21 +++++++++++++++++++++
 2 files changed, 36 insertions(+)

diff --git a/Observable.js b/Observable.js
index 03545cd..abed522 100644
--- a/Observable.js
+++ b/Observable.js
@@ -11,12 +11,20 @@ class ObserverList {
   }
   add(observer) {
     // todo add observer to list
+    this.observerList.push(observer);
   }
   remove(observer) {
     // todo remove observer from list
+    this.observerList = this.observerList.filter(item => item !== observer);
   }
   count() {
     // return observer list size
+    return this.observerList.length;
+  }
+  get(index) {
+    if (index > -1 && index < this.observerList.length) {
+      return this.observerList[index];
+    }
   }
 }
 
@@ -26,12 +34,19 @@ 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 i = 0,
+      len = this.observers.count();
+    for (i = 0; i < len; i++) {
+      this.observers.get(i).update(...args);
+    }
   }
 }
 
diff --git a/PubSub.js b/PubSub.js
index 0c7999e..bb9358b 100644
--- a/PubSub.js
+++ b/PubSub.js
@@ -13,14 +13,35 @@ module.exports = class PubSub {
 
   subscribe(type, fn) {
     // todo subscribe
+    if (!this.subscribers[type]) {
+      this.subscribers[type] = [];
+    }
+    this.subscribers[type].push({ fn: fn });
   }
 
   unsubscribe(type, fn) {
     // todo unsubscribe
+    if (this.subscribers[type]) {
+      var len = this.subscribers[type].length;
+      for (var i = 0; i < len; i++) {
+        if (this.subscribers[type][i].fn === fn) {
+          this.subscribers[type].splice(i, 1);
+          break;
+        }
+      }
+    }
   }
 
   publish(type, ...args) {
     // todo publish
+    if (!this.subscribers[type]) {
+      return false;
+    }
+    var typeSubs = this.subscribers[type],
+      len = typeSubs ? typeSubs.length : 0;
+    while (len--) {
+      typeSubs[len].fn(...args);
+    }
   }
 
 }