Add web front-end and fix API issues

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

@@ -0,0 +1,11 @@
+import { operate } from '../util/lift';
+import { mergeInternals } from './mergeInternals';
+export function mergeScan(accumulator, seed, concurrent = Infinity) {
+    return operate((source, subscriber) => {
+        let state = seed;
+        return mergeInternals(source, subscriber, (value, index) => accumulator(state, value, index), concurrent, (value) => {
+            state = value;
+        }, false, undefined, () => (state = null));
+    });
+}
+//# sourceMappingURL=mergeScan.js.map