How is the best practice to handle timezones in a grid for example.

I am sending in the JSON the date as milliseconds. I know this was saved before as UTC.

for example

Code:
validFrom:1490133600000
Now I was thinking that i'll convert the date to my specific timezone with moment in the column renderer in the front-end.


Code:
xtype: 'datecolumn',  
itemId: 'clmFrom',
format:'m/d/Y h:i A',
dataIndex: 'validFrom',
text: 'From',
renderer: function(val, meta, record, rowIndex) {
return return moment(val.getTime()).tz("America/Los_Angeles").format('MM/DD/YYYY HH:mm A');
}

But the date is obviously already the local timezone, since I am sending it as milliseconds which does not include timezone informations.So moment will not execute the conversation.

Had somebody a similar problem in the past to support different timezones.