google-timezones-json

import timezones from 'google-timezones-json';
// var timezones = require('google-timezones-json');
console.log(timezones);

{
    "Pacific/Niue": "(GMT-11:00) Niue",
    "Pacific/Pago_Pago": "(GMT-11:00) Pago Pago",
    "Pacific/Honolulu": "(GMT-10:00) Hawaii Time",
    ...
}