initial commit: scaffolding

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diff --git a/node_modules/rxjs/src/internal/operators/windowCount.ts b/node_modules/rxjs/src/internal/operators/windowCount.ts
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+import { Observable } from '../Observable';
+import { Subject } from '../Subject';
+import { OperatorFunction } from '../types';
+import { operate } from '../util/lift';
+import { createOperatorSubscriber } from './OperatorSubscriber';
+
+/**
+ * Branch out the source Observable values as a nested Observable with each
+ * nested Observable emitting at most `windowSize` values.
+ *
+ * <span class="informal">It's like {@link bufferCount}, but emits a nested
+ * Observable instead of an array.</span>
+ *
+ * ![](windowCount.png)
+ *
+ * Returns an Observable that emits windows of items it collects from the source
+ * Observable. The output Observable emits windows every `startWindowEvery`
+ * items, each containing no more than `windowSize` items. When the source
+ * Observable completes or encounters an error, the output Observable emits
+ * the current window and propagates the notification from the source
+ * Observable. If `startWindowEvery` is not provided, then new windows are
+ * started immediately at the start of the source and when each window completes
+ * with size `windowSize`.
+ *
+ * ## Examples
+ *
+ * Ignore every 3rd click event, starting from the first one
+ *
+ * ```ts
+ * import { fromEvent, windowCount, map, skip, mergeAll } from 'rxjs';
+ *
+ * const clicks = fromEvent(document, 'click');
+ * const result = clicks.pipe(
+ *   windowCount(3),
+ *   map(win => win.pipe(skip(1))), // skip first of every 3 clicks
+ *   mergeAll()                     // flatten the Observable-of-Observables
+ * );
+ * result.subscribe(x => console.log(x));
+ * ```
+ *
+ * Ignore every 3rd click event, starting from the third one
+ *
+ * ```ts
+ * import { fromEvent, windowCount, mergeAll } from 'rxjs';
+ *
+ * const clicks = fromEvent(document, 'click');
+ * const result = clicks.pipe(
+ *   windowCount(2, 3),
+ *   mergeAll() // flatten the Observable-of-Observables
+ * );
+ * result.subscribe(x => console.log(x));
+ * ```
+ *
+ * @see {@link window}
+ * @see {@link windowTime}
+ * @see {@link windowToggle}
+ * @see {@link windowWhen}
+ * @see {@link bufferCount}
+ *
+ * @param windowSize The maximum number of values emitted by each window.
+ * @param startWindowEvery Interval at which to start a new window. For example
+ * if `startWindowEvery` is `2`, then a new window will be started on every
+ * other value from the source. A new window is started at the beginning of the
+ * source by default.
+ * @return A function that returns an Observable of windows, which in turn are
+ * Observable of values.
+ */
+export function windowCount<T>(windowSize: number, startWindowEvery: number = 0): OperatorFunction<T, Observable<T>> {
+  const startEvery = startWindowEvery > 0 ? startWindowEvery : windowSize;
+
+  return operate((source, subscriber) => {
+    let windows = [new Subject<T>()];
+    let starts: number[] = [];
+    let count = 0;
+
+    // Open the first window.
+    subscriber.next(windows[0].asObservable());
+
+    source.subscribe(
+      createOperatorSubscriber(
+        subscriber,
+        (value: T) => {
+          // Emit the value through all current windows.
+          // We don't need to create a new window yet, we
+          // do that as soon as we close one.
+          for (const window of windows) {
+            window.next(value);
+          }
+          // Here we're using the size of the window array to figure
+          // out if the oldest window has emitted enough values. We can do this
+          // because the size of the window array is a function of the values
+          // seen by the subscription. If it's time to close it, we complete
+          // it and remove it.
+          const c = count - windowSize + 1;
+          if (c >= 0 && c % startEvery === 0) {
+            windows.shift()!.complete();
+          }
+
+          // Look to see if the next count tells us it's time to open a new window.
+          // TODO: We need to figure out if this really makes sense. We're technically
+          // emitting windows *before* we have a value to emit them for. It's probably
+          // more expected that we should be emitting the window when the start
+          // count is reached -- not before.
+          if (++count % startEvery === 0) {
+            const window = new Subject<T>();
+            windows.push(window);
+            subscriber.next(window.asObservable());
+          }
+        },
+        () => {
+          while (windows.length > 0) {
+            windows.shift()!.complete();
+          }
+          subscriber.complete();
+        },
+        (err) => {
+          while (windows.length > 0) {
+            windows.shift()!.error(err);
+          }
+          subscriber.error(err);
+        },
+        () => {
+          starts = null!;
+          windows = null!;
+        }
+      )
+    );
+  });
+}