Add web front-end and fix API issues

node_modules/rxjs/dist/cjs/internal/operators/elementAt.js

@@ -0,0 +1,19 @@
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+exports.elementAt = void 0;
+var ArgumentOutOfRangeError_1 = require("../util/ArgumentOutOfRangeError");
+var filter_1 = require("./filter");
+var throwIfEmpty_1 = require("./throwIfEmpty");
+var defaultIfEmpty_1 = require("./defaultIfEmpty");
+var take_1 = require("./take");
+function elementAt(index, defaultValue) {
+    if (index < 0) {
+        throw new ArgumentOutOfRangeError_1.ArgumentOutOfRangeError();
+    }
+    var hasDefaultValue = arguments.length >= 2;
+    return function (source) {
+        return source.pipe(filter_1.filter(function (v, i) { return i === index; }), take_1.take(1), hasDefaultValue ? defaultIfEmpty_1.defaultIfEmpty(defaultValue) : throwIfEmpty_1.throwIfEmpty(function () { return new ArgumentOutOfRangeError_1.ArgumentOutOfRangeError(); }));
+    };
+}
+exports.elementAt = elementAt;
+//# sourceMappingURL=elementAt.js.map