if(!value) return '';
var tz = (options&&options.tz)||def_tz;
var m = dayjs(value);
if ( ! value.match(/^\d{4}-\d{2}-\d{2}$/ ) ) {
if ( ! value.toString().match(/^\d{4}-\d{2}-\d{2}$/ ) ) {
m = m.tz(tz);
}
-