Add web front-end and fix API issues

node_modules/rxjs/dist/esm5/internal/operators/endWith.js

@@ -0,0 +1,11 @@
+import { __read, __spreadArray } from "tslib";
+import { concat } from '../observable/concat';
+import { of } from '../observable/of';
+export function endWith() {
+    var values = [];
+    for (var _i = 0; _i < arguments.length; _i++) {
+        values[_i] = arguments[_i];
+    }
+    return function (source) { return concat(source, of.apply(void 0, __spreadArray([], __read(values)))); };
+}
+//# sourceMappingURL=endWith.js.map