fix: front-end improvements

makes some fields visible and other hidden depending on the result of
some API calls, e.g. visitor is logged in -> show "Log out" button

WebApp/wwwroot/js/generalUseHelpers.js

@@ -0,0 +1,38 @@
+var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, generator) {
+    function adopt(value) { return value instanceof P ? value : new P(function (resolve) { resolve(value); }); }
+    return new (P || (P = Promise))(function (resolve, reject) {
+        function fulfilled(value) { try { step(generator.next(value)); } catch (e) { reject(e); } }
+        function rejected(value) { try { step(generator["throw"](value)); } catch (e) { reject(e); } }
+        function step(result) { result.done ? resolve(result.value) : adopt(result.value).then(fulfilled, rejected); }
+        step((generator = generator.apply(thisArg, _arguments || [])).next());
+    });
+};
+export function unhideElementById(document, e) {
+    return __awaiter(this, void 0, void 0, function* () {
+        var element = document.getElementById(e);
+        if (element) {
+            element.classList.remove('hidden-before-load');
+            console.log(element.classList);
+        }
+    });
+}
+export function getEvent(id) {
+    return __awaiter(this, void 0, void 0, function* () {
+        const res = yield fetch("/api/events/" + id);
+        if (!res.ok) {
+            throw Error("To wydarzenie nie istnieje");
+        }
+        const events = yield res.json();
+        return events;
+    });
+}
+export function getMyAccount() {
+    return __awaiter(this, void 0, void 0, function* () {
+        const res = yield fetch("/api/auth/my_account");
+        if (!res.ok) {
+            throw Error("Użytkownik niezalogowany!");
+        }
+        const data = yield res.json();
+        return data;
+    });
+}