Add web front-end and fix API issues

node_modules/rxjs/dist/cjs/internal/util/EmptyError.js

@@ -0,0 +1,12 @@
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+exports.EmptyError = void 0;
+var createErrorClass_1 = require("./createErrorClass");
+exports.EmptyError = createErrorClass_1.createErrorClass(function (_super) {
+    return function EmptyErrorImpl() {
+        _super(this);
+        this.name = 'EmptyError';
+        this.message = 'no elements in sequence';
+    };
+});
+//# sourceMappingURL=EmptyError.js.map