Fix bug where Subscription fails to parse expirationTime in IE11 (#78)

* Fix bug where Subscription fails to parse expirationTime in IE11
* move iso string conversion logic into parseISOString helper function

src/subscription/Subscription-spec.js

@@ -1,9 +1,9 @@
 describe('RingCentral.subscription.Subscription', function() {
 
     var pollInterval = 1;
-    var renewHandicapMs = 1;
+    var renewHandicapMs = 30;
     var expiresIn = 100; // 100 seconds
-    var quickExpiresIn = 0.1; // 50 ms
+    var quickExpiresIn = 0.5; // 50 ms
 
     function createSubscription(sdk) {
         return sdk.createSubscription({
@@ -41,6 +41,33 @@ describe('RingCentral.subscription.Subscription', function() {
 
         }));
 
+        it('automatically renews subscription with +0000 timezone format', asyncTest(function(sdk) {
+
+            subscribeGeneric(quickExpiresIn, null, null, '+0000');
+            subscribeGeneric(10, 'foo-bar-baz'); // should be a good value for future response
+
+            var subscription = createSubscription(sdk);
+
+            return subscription
+                .setEventFilters(['foo', 'bar'])
+                .register()
+                .then(function(res) {
+
+                    expect(res.json().expiresIn).to.equal(quickExpiresIn);
+
+                    return new Promise(function(resolve, reject) {
+                        subscription.on(subscription.events.automaticRenewError, function(e) {
+                            reject(e);
+                        });
+                        subscription.on(subscription.events.automaticRenewSuccess, function() {
+                            resolve(null);
+                        });
+                    });
+
+                });
+
+        }));
+
         it('captures automatic subscription renew errors', asyncTest(function(sdk) {
 
             subscribeGeneric(quickExpiresIn);

src/subscription/Subscription.js

@@ -1,5 +1,25 @@
 var EventEmitter = require("events").EventEmitter;
 
+// detect ISO 8601 format string with +00[:00] timezone notations
+var ISO_REG_EXP = /(\+[\d]{2}):?([\d]{2})?$/;
+
+function buildIEFriendlyString(match, $1, $2) {
+    return $1 + ':' + ($2 || '00');
+}
+
+/**
+ *
+ * @param {string} time
+ * @return {number}
+ */
+function parseISOString(time) {
+    time = time || 0;
+    if (typeof time === 'string') {
+        return Date.parse(time.replace(ISO_REG_EXP, buildIEFriendlyString));
+    }
+    return time;
+}
+
 /**
  * @param {Platform} options.platform
  * @param {Externals} options.externals
@@ -87,11 +107,14 @@ Subscription.prototype.alive = function() {
  */
 Subscription.prototype.expired = function() {
     if (!this.subscribed()) return true;
-    return !this.subscribed() || Date.now() > this.subscription().expirationTime;
+    return !this.subscribed() || Date.now() > parseISOString(this.subscription().expirationTime);
 };
 
+/**
+ * @return {number}
+ */
 Subscription.prototype.expirationTime = function() {
-    return new Date(this.subscription().expirationTime || 0).getTime() - this._renewHandicapMs;
+    return parseISOString(this.subscription().expirationTime) - this._renewHandicapMs;
 };
 
 /**
@@ -473,7 +496,7 @@ module.exports = Subscription;
  * @property {string} [id]
  * @property {string} [uri]
  * @property {string[]} [eventFilters]
- * @property {string} [expirationTime] Format: 2014-03-12T19:54:35.613Z
+ * @property {string} [expirationTime] Format: 2014-03-12T19:54:35.613+0000
  * @property {int} [expiresIn]
  * @property {string} [deliveryMode.transportType]
  * @property {boolean} [deliveryMode.encryption]