restore pubnub when network is back online (#86)

* restore pubnub when network is back online

* fix typo

Author: embbnux

demo/core.html

@@ -100,6 +100,16 @@ <h1>
                 subscription.on(subscription.events.notification, function(msg) {
                     cb(msg.body);
                 });
+                subscription.on(subscription.events.renewError, function() {
+                    subscription.reset();
+                    subscription = null;
+                    getPresenceSubscription(event, cb);
+                });
+                subscription.on(subscription.events.subscribeError, function() {
+                    subscription.reset();
+                    subscription = null;
+                    getPresenceSubscription(event, cb);
+                });
 
                 subscription
                     .restore([event])

src/subscription/Subscription.js

@@ -212,7 +212,8 @@ Subscription.prototype.subscribe = function() {
     }.bind(this)).catch(function(e) {
 
         e = this._platform.client().makeError(e);
-
+        // `reset` will remove pubnub instance.
+        // so if network is broken for a long time, pubnub will be removed. And client can not receive notification anymore.
         this.reset()
             .emit(this.events.subscribeError, e);
 
@@ -251,7 +252,8 @@ Subscription.prototype.renew = function() {
     }.bind(this)).catch(function(e) {
 
         e = this._platform.client().makeError(e);
-
+        // `reset` will remove pubnub instance.
+        // so if network is broken for a long time, pubnub will be removed. And client can not receive notification anymore.
         this.reset()
             .emit(this.events.renewError, e);
 
@@ -450,6 +452,7 @@ Subscription.prototype._subscribeAtPubnub = function() {
 
         this._pubnub = new PubNub({
             ssl: true,
+            restore: true,
             subscribeKey: deliveryMode.subscriberKey
         });