fix(util-frontend): revert typescript conversion

src/util-frontend.js

@@ -0,0 +1,51 @@
+import dayjs from "dayjs";
+import timezone from "dayjs/plugin/timezone";
+import utc from "dayjs/plugin/utc";
+import timezones from "timezones-list";
+
+dayjs.extend(utc)
+dayjs.extend(timezone)
+
+function getTimezoneOffset(timeZone) {
+    const now = new Date();
+    const tzString = now.toLocaleString("en-US", {
+        timeZone,
+    });
+    const localString = now.toLocaleString("en-US");
+    const diff = (Date.parse(localString) - Date.parse(tzString)) / 3600000;
+    const offset = diff + now.getTimezoneOffset() / 60;
+    return -offset;
+}
+
+export function timezoneList() {
+    let result = [];
+
+    for (let timezone of timezones) {
+        try {
+            let display = dayjs().tz(timezone.tzCode).format("Z");
+
+            result.push({
+                name: `(UTC${display}) ${timezone.tzCode}`,
+                value: timezone.tzCode,
+                time: getTimezoneOffset(timezone.tzCode),
+            })
+        } catch (e) {
+            console.error(e.message);
+            console.log("Skip this timezone");
+        }
+    }
+
+    result.sort((a, b) => {
+        if (a.time > b.time) {
+            return 1;
+        }
+
+        if (b.time > a.time) {
+            return -1;
+        }
+
+        return 0;
+    })
+
+    return result;
+}