use moment to detect timezones

services/tzupdate.js

@@ -0,0 +1,32 @@
+'use strict';
+
+// This script re-calculates timezone offsets once a day
+
+let moment = require('moment-timezone');
+let db = require('../lib/db');
+
+function updateTimezoneOffsets(callback) {
+    db.getConnection((err, connection) => {
+        if (err) {
+            return callback(err);
+        }
+
+        let values = [];
+        moment.tz.names().forEach(tz => {
+            let time = moment();
+            values.push('(' + connection.escape(tz.toLowerCase().trim()) + ',' + connection.escape(time.tz(tz).utcOffset()) + ')');
+        });
+
+        let query = 'INSERT INTO tzoffset (`tz`, `offset`) VALUES ' + values.join(', ') + ' ON DUPLICATE KEY UPDATE `offset` = VALUES(`offset`)';
+
+        connection.query(query, values, (err, result) => {
+            connection.release();
+            if (err) {
+                return callback(err);
+            }
+            return callback(null, result);
+        });
+    });
+}
+
+updateTimezoneOffsets(console.log);