it seems that results from Ext.Date.localToUtc and Ext.Date.utcToLocal must be inverted.
var localTime = new Date(); // ROMANIA
var londonTime = Ext.Date.localToUtc(localTime);
console.log('Initial:', localTime);
console.log('London :', londonTime);
console.log('MyTime :', Ext.Date.utcToLocal(londonTime));
console.log('UTC! :', Ext.Date.format(localTime, 'C'));
results for Romania Time zone (GMT+2):
Initial: Thu Jan 23 2020 17:48:09 GMT+0200 (Eastern European Standard Time)
London : Thu Jan 23 2020 19:48:09 GMT+0200 (Eastern European Standard Time)
MyTime : Thu Jan 23 2020 17:48:09 GMT+0200 (Eastern European Standard Time)
UTC! : 2020-01-23T15:48:09.656Z
any thoughts?