diff core/misc/timezone.es6.js @ 0:c75dbcec494b

Initial commit from drush-created site

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/core/misc/timezone.es6.js	Thu Jul 05 14:24:15 2018 +0000
@@ -0,0 +1,72 @@
+/**
+ * @file
+ * Timezone detection.
+ */
+
+(function ($, Drupal) {
+  /**
+   * Set the client's system time zone as default values of form fields.
+   *
+   * @type {Drupal~behavior}
+   */
+  Drupal.behaviors.setTimezone = {
+    attach(context, settings) {
+      const $timezone = $(context).find('.timezone-detect').once('timezone');
+      if ($timezone.length) {
+        const dateString = Date();
+        // In some client environments, date strings include a time zone
+        // abbreviation, between 3 and 5 letters enclosed in parentheses,
+        // which can be interpreted by PHP.
+        const matches = dateString.match(/\(([A-Z]{3,5})\)/);
+        const abbreviation = matches ? matches[1] : 0;
+
+        // For all other client environments, the abbreviation is set to "0"
+        // and the current offset from UTC and daylight saving time status are
+        // used to guess the time zone.
+        const dateNow = new Date();
+        const offsetNow = dateNow.getTimezoneOffset() * -60;
+
+        // Use January 1 and July 1 as test dates for determining daylight
+        // saving time status by comparing their offsets.
+        const dateJan = new Date(dateNow.getFullYear(), 0, 1, 12, 0, 0, 0);
+        const dateJul = new Date(dateNow.getFullYear(), 6, 1, 12, 0, 0, 0);
+        const offsetJan = dateJan.getTimezoneOffset() * -60;
+        const offsetJul = dateJul.getTimezoneOffset() * -60;
+
+        let isDaylightSavingTime;
+        // If the offset from UTC is identical on January 1 and July 1,
+        // assume daylight saving time is not used in this time zone.
+        if (offsetJan === offsetJul) {
+          isDaylightSavingTime = '';
+        }
+        // If the maximum annual offset is equivalent to the current offset,
+        // assume daylight saving time is in effect.
+        else if (Math.max(offsetJan, offsetJul) === offsetNow) {
+          isDaylightSavingTime = 1;
+        }
+        // Otherwise, assume daylight saving time is not in effect.
+        else {
+          isDaylightSavingTime = 0;
+        }
+
+        // Submit request to the system/timezone callback and set the form
+        // field to the response time zone. The client date is passed to the
+        // callback for debugging purposes. Submit a synchronous request to
+        // avoid database errors associated with concurrent requests
+        // during install.
+        const path = `system/timezone/${abbreviation}/${offsetNow}/${isDaylightSavingTime}`;
+        $.ajax({
+          async: false,
+          url: Drupal.url(path),
+          data: { date: dateString },
+          dataType: 'json',
+          success(data) {
+            if (data) {
+              $timezone.val(data);
+            }
+          },
+        });
+      }
+    },
+  };
+}(jQuery, Drupal));