control flow changes?

src/main.js

@@ -29,9 +29,8 @@ function showPlaceholder() {
 }
 
 function hidePlaceholder() {
-placeholder_message.style.display = "none";
+  placeholder_message.style.display = "none";
   cal_ele.style.display = "block";
-
 }
 
 const new_tippy = (info) => {
@@ -74,54 +73,58 @@ const tippy_die = (info) => {
 confirm_button.addEventListener("click", (_e) => {
   console.log("nawgh:", text_field.value);
   const url = create_url(text_field.value);
-  if (url) {
-    hidePlaceholder(); // Hide placeholder when loading starts
-    if (calendar) calendar.destroy();
-    calendar = new Calendar(cal_ele, {
-      // calendar config
-      plugins: [
-        bootstrap5Plugin,
-        listPlugin,
-        iCalendarPlugin,
-        timeGridPlugin,
-        dayGridPlugin,
-      ],
-      themeSystem: "bootstrap5", // Enable Bootstrap 5 theme
-      initialView: "listWeek",
-      // multiMonthMaxColumns: 1,
-      navLinks: true,
-      dayMaxEvents: true,
-      eventMaxStack: 3,
-      dayMaxEventRows: true,
-      nowIndicator: true,
-      weekNumbers: true,
-      headerToolbar: {
-        left: "prev,next",
-        center: "title",
-        right: "today dayGridMonth,timeGridWeek,timeGridDay,listMonth",
-        // views
-      },
-      views: {
-        dayGridMonth: { buttonText: "Month" },
-        timeGridWeek: { buttonText: "Week" },
-        timeGridDay: { buttonText: "Day" },
-        listMonth: { buttonText: "List" },
-      },
+  if (!url && text_field.value) return alert("Please input valid url.");
 
-      events: {
-        url: url,
-        format: "ics",
-        color: getNextColor(),
-      },
-      // eventClick: new_tippy,
-      eventMouseEnter: new_tippy,
-      eventMouseLeave: tippy_die,
-    });
-    // end calendar config
-    calendar.render();
-  } else if (!calendar) {
+  if (calendar) calendar.destroy();
+
+  if (!text_field.value /* && !calendar */) {
     showPlaceholder(); // Show placeholder if no URL is provided
+    return;
   }
+
+  hidePlaceholder(); // Hide placeholder when loading starts
+  calendar = new Calendar(cal_ele, {
+    // calendar config
+    plugins: [
+      bootstrap5Plugin,
+      listPlugin,
+      iCalendarPlugin,
+      timeGridPlugin,
+      dayGridPlugin,
+    ],
+    themeSystem: "bootstrap5", // Enable Bootstrap 5 theme
+    initialView: "listWeek",
+    // multiMonthMaxColumns: 1,
+    navLinks: true,
+    dayMaxEvents: true,
+    eventMaxStack: 3,
+    dayMaxEventRows: true,
+    nowIndicator: true,
+    weekNumbers: true,
+    headerToolbar: {
+      left: "prev,next",
+      center: "title",
+      right: "today dayGridMonth,timeGridWeek,timeGridDay,listMonth",
+      // views
+    },
+    views: {
+      dayGridMonth: { buttonText: "Month" },
+      timeGridWeek: { buttonText: "Week" },
+      timeGridDay: { buttonText: "Day" },
+      listMonth: { buttonText: "List" },
+    },
+
+    events: {
+      url: url,
+      format: "ics",
+      color: getNextColor(),
+    },
+    // eventClick: new_tippy,
+    eventMouseEnter: new_tippy,
+    eventMouseLeave: tippy_die,
+  });
+  // end calendar config
+  calendar.render();
 });
 
 // text_field.value = "http://127.0.0.1:8080/filtered-ics";
@@ -129,7 +132,10 @@ confirm_button.addEventListener("click", (_e) => {
 // wow
 
 add_button.addEventListener("click", () => {
-  if (calendar && text_field.value) {
+  if (calendar) {
+    const url = create_url(text_field.value);
+    if (!url)
+      return text_field.value ? alert("Please input valid url.") : undefined;
     calendar.addEventSource({
       url: text_field.value,
       format: "ics",

src/utils.js

@@ -1,9 +1,10 @@
 function create_url(url) {
   try {
     return new URL(url);
-  } catch {
+  } catch (e) {
+    // console.info(e);
     return null;
   }
 }
 
-export { create_url }
+export { create_url };