Add web front-end and fix API issues

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

@@ -0,0 +1,22 @@
+import { identity } from '../util/identity';
+import { operate } from '../util/lift';
+import { createOperatorSubscriber } from './OperatorSubscriber';
+export function distinctUntilChanged(comparator, keySelector = identity) {
+    comparator = comparator !== null && comparator !== void 0 ? comparator : defaultCompare;
+    return operate((source, subscriber) => {
+        let previousKey;
+        let first = true;
+        source.subscribe(createOperatorSubscriber(subscriber, (value) => {
+            const currentKey = keySelector(value);
+            if (first || !comparator(previousKey, currentKey)) {
+                first = false;
+                previousKey = currentKey;
+                subscriber.next(value);
+            }
+        }));
+    });
+}
+function defaultCompare(a, b) {
+    return a === b;
+}
+//# sourceMappingURL=distinctUntilChanged.js.map