fix(windowToggle): fix window closing and unsubscription semantics

Fix windowToggle in order to unsubscribe inner windows whenever the outer
Observable is unsubscribed. Also allow windows to be closed when the
closingNotifier Observables complete without having emitted a 'next'
value previously. Also only open a new window if the closingSelector
hasn't thrown an error.

src/operators/windowToggle.ts

@@ -27,8 +27,13 @@ class WindowToggleOperator<T, R, O> implements Operator<T, R> {
   }
 }
 
+interface WindowContext<T> {
+  window: Subject<T>;
+  subscription: Subscription<T>;
+}
+
 class WindowToggleSubscriber<T, O> extends Subscriber<T> {
-  private windows: Subject<T>[] = [];
+  private contexts: Array<WindowContext<T>> = [];
   private closingNotification: Subscription<any>;
 
   constructor(destination: Subscriber<T>,
@@ -39,55 +44,56 @@ class WindowToggleSubscriber<T, O> extends Subscriber<T> {
   }
 
   _next(value: T) {
-    const windows = this.windows;
-    const len = windows.length;
+    const contexts = this.contexts;
+    const len = contexts.length;
     for (let i = 0; i < len; i++) {
-      windows[i].next(value);
+      contexts[i].window.next(value);
     }
   }
 
   _error(err: any) {
-    const windows = this.windows;
-    while (windows.length > 0) {
-      windows.shift().error(err);
+    const contexts = this.contexts;
+    while (contexts.length > 0) {
+      contexts.shift().window.error(err);
     }
     this.destination.error(err);
   }
 
   _complete() {
-    const windows = this.windows;
-    while (windows.length > 0) {
-      windows.shift().complete();
+    const contexts = this.contexts;
+    while (contexts.length > 0) {
+      const context = contexts.shift();
+      context.window.complete();
+      context.subscription.unsubscribe();
     }
     this.destination.complete();
   }
 
   openWindow(value: O) {
-    const window = new Subject<T>();
-    this.windows.push(window);
-    this.destination.next(window);
-    let windowContext = {
-      window,
-      subscription: new Subscription()
-    };
-
     const closingSelector = this.closingSelector;
     let closingNotifier = tryCatch(closingSelector)(value);
     if (closingNotifier === errorObject) {
       this.error(closingNotifier.e);
     } else {
-      const subscriber = new WindowClosingNotifierSubscriber<T, O>(this, windowContext);
+      let context = {
+        window: new Subject<T>(),
+        subscription: new Subscription()
+      };
+      this.contexts.push(context);
+      this.destination.next(context.window);
+      const subscriber = new WindowClosingNotifierSubscriber<T, O>(this, context);
       const subscription = closingNotifier._subscribe(subscriber);
-      this.add(windowContext.subscription.add(subscription));
+      this.add(context.subscription.add(subscription));
     }
   }
 
-  closeWindow(windowContext: { subscription: Subscription<T>, window: Subject<T> }) {
-    const { window, subscription } = windowContext;
-    const windows = this.windows;
-    windows.splice(windows.indexOf(window), 1);
+  closeWindow(context: WindowContext<T>) {
+    const { window, subscription } = context;
+    const contexts = this.contexts;
+    contexts.splice(contexts.indexOf(context), 1);
     window.complete();
     this.remove(subscription);
+    subscription.unsubscribe();
   }
 }
 
@@ -106,7 +112,7 @@ class WindowClosingNotifierSubscriber<T, O> extends Subscriber<T> {
   }
 
   _complete() {
-    // noop
+    this.parent.closeWindow(this.windowContext);
   }
 }