Add web front-end and fix API issues

node_modules/rxjs/dist/esm/internal/operators/pairwise.js

@@ -0,0 +1,15 @@
+import { operate } from '../util/lift';
+import { createOperatorSubscriber } from './OperatorSubscriber';
+export function pairwise() {
+    return operate((source, subscriber) => {
+        let prev;
+        let hasPrev = false;
+        source.subscribe(createOperatorSubscriber(subscriber, (value) => {
+            const p = prev;
+            prev = value;
+            hasPrev && subscriber.next([p, value]);
+            hasPrev = true;
+        }));
+    });
+}
+//# sourceMappingURL=pairwise.js.map