Get the same date string from a Date object, no matter the timezone of the server.
function tzDate(utcPrefix = 'Sat, 01 Jan 2011 12:00:00') {
let tz = new Date().toUTCString().split(' ')
tz = tz[tz.length - 1] // local TZ
return new Date(`${utcPrefix} ${tz}`)
}