perf: avoid the layout shift for post datetime

_javascript/commons/locale-helper.js

@@ -1,19 +0,0 @@
-/**
- * A tool for locale datetime
- */
-
-const LocaleHelper = (function () {
-  const $preferLocale = $('meta[name="prefer-datetime-locale"]');
-  const locale = $preferLocale.length > 0 ?
-      $preferLocale.attr('content').toLowerCase() : $('html').attr('lang').substr(0, 2);
-  const attrTimestamp = 'data-ts';
-  const attrDateFormat = 'data-df';
-
-  return {
-    locale: () => locale,
-    attrTimestamp: () => attrTimestamp,
-    attrDateFormat: () => attrDateFormat,
-    getTimestamp: ($elem) => Number($elem.attr(attrTimestamp)),  // unix timestamp
-    getDateFormat: ($elem) => $elem.attr(attrDateFormat)
-  };
-}());