Get User’s Country Based on Time Zone in JavaScript [closed]

I want to determine the user’s country based on their time zone in JavaScript without using any IP-to-location service (like maxmind, ipregistry or ip2location). The following code uses the moment-timezone library to map time zones to countries and returns either the matching country or the original time zone if no match is found.

// Import the moment-timezone library
const moment = require('moment-timezone');

/**
 * Get the user's country based on their time zone.
 * @param {string} userTimeZone - The user's time zone.
 * @returns {string} The user's country or the original time zone if not found.
 */
function getCountryByTimeZone(userTimeZone) {
  // Get a list of countries from moment-timezone
  const countries = moment.tz.countries();

  // Iterate through the countries and check if the time zone is associated with any country
  for (const country of countries) {
    const timeZones = moment.tz.zonesForCountry(country);

    if (timeZones.includes(userTimeZone)) {
      // Use Intl.DisplayNames to get the full country name
      const countryName = new Intl.DisplayNames(['en'], { type: 'region' }).of(country);
      return countryName;
    }
  }

  // Return the original time zone if no matching country is found
  return userTimeZone;
}

// Example usage
const userTimeZone = Intl.DateTimeFormat().resolvedOptions().timeZone;
const userCountry = getCountryByTimeZone(userTimeZone);
console.log('User country based on time zone:', userCountry);

Usage:

Copy and paste the provided code into your JavaScript environment.
Call the getCountryByTimeZone function with the user’s time zone to retrieve the user’s country.
The function returns either the matching country or the original time zone if no match is found.
Note:

Make sure to have the moment-timezone library installed in your project.
The accuracy of the result depends on the completeness and accuracy of the time zone data provided by the library.