This package allows to cast from TZ windows timezone to TZ unix timezone
const casttz = require('timezone-cast');
console.log(casttz.toUnix('BG'));
//Europe/London
console.log(casttz.toUnix('Europe/London'));
//Europe/London
console.log(casttz.toUnix('GMT Standard Time'));
//Europe/London
console.log(casttz.toWindows('BG'));
//GMT Standard Time
console.log(casttz.toWindows('Europe/London'));
//GMT Standard Time
console.log(casttz.toWindows('GMT Standard Time'));
//GMT Standard Time