I am looking for a function to convert date in one timezone to another.
It need two parameters,
You can use to toLocaleString() method for setting the timezone.
new Date().toLocaleString('en-US', { timeZone: 'Indian/Christmas' })
For India you can use "Indian/Christmas" and the following are the various timeZones,
"Antarctica/Davis",
"Asia/Bangkok",
"Asia/Hovd",
"Asia/Jakarta",
"Asia/Phnom_Penh",
"Asia/Pontianak",
"Asia/Saigon",
"Asia/Vientiane",
"Etc/GMT-7",
"Indian/Christmas"