JavaScript Time Zone Detect

Common errors

• ReferenceError: jstz is not defined

  cause The jstz script file was not loaded or executed in the browser environment before attempting to use the `jstz` global object.
  fix Ensure that `<script src="path/to/jstz.min.js"></script>` is included in your HTML before any code that tries to use `jstz`.

• ReferenceError: require is not defined

  cause Attempting to use `require('jstimezonedetect')` in a browser environment or a pure ESM Node.js module without a compatible bundler or transpilation.
  fix For browsers, load the script via a `<script>` tag. For ESM modules in Node.js, you might need to use `import jstz from 'jstimezonedetect';` with appropriate `type: 'module'` in package.json or rely on a bundler like Webpack or Rollup to handle CommonJS interoperability.

• TypeError: jstz.determine is not a function

  cause The `jstz` object was not correctly imported or exposed, meaning the `determine` method is unavailable.
  fix Verify your import statement (e.g., `const jstz = require('jstimezonedetect');` for CJS) or ensure the global `jstz` object is available in the browser. Check if other scripts are overwriting the `jstz` global.

Warnings

• gotcha jstimezonedetect explicitly focuses on modern time zones (from 2010 onwards) and does not provide historical time zone data. It will not detect differences in UTC offsets for dates prior to 2010.
  Fix: If historical time zone data is required, consider a more comprehensive library like `moment-timezone` or `luxon`.
• gotcha This library does not perform geo-location. It determines the time zone based on the device's system settings, not its physical location. As such, it won't differentiate between zones with identical modern rules but different geographical names (e.g., 'Europe/Berlin' vs 'Europe/Stockholm').
  Fix: For geo-location based time zone detection, you would need to integrate with a separate geo-location service or library that provides time zone information based on coordinates.
• gotcha The project appears to be in maintenance mode, with its last release in 2018. This means it may not receive updates for changes in IANA time zone rules, potentially leading to outdated or incorrect time zone detections in regions with recent rule adjustments.
  Fix: For applications requiring up-to-date time zone rules, consider libraries that are actively maintained and frequently update their time zone data, such as `luxon` or `date-fns-tz`.
• gotcha The library might not provide a consistent IANA time zone name across all browsers or operating systems, as it relies on internal browser/OS heuristics to determine the zone. While it aims for IANA keys, the underlying mechanism can vary.
  Fix: Test thoroughly across target environments. If inconsistencies are critical, consider explicit user input or a server-side detection fallback.

Install

• npm install jstimezonedetect npm
• yarn add jstimezonedetect yarn
• pnpm add jstimezonedetect pnpm

Imports

• jstz
  wrong:

  import jstz from 'jstimezonedetect';

  correct:

  const jstz = require('jstimezonedetect');

  Primarily a CommonJS module for Node.js environments. For ESM, direct import might require a compatibility layer or bundler configuration.
• jstz (browser global)

  // Include <script src="path/to/dist/jstz.min.js"></script>
  // 'jstz' object is then available globally

  For web environments, the library exposes the 'jstz' object directly onto the global scope after the script is loaded.

Quickstart

Demonstrates how to use jstimezonedetect in a Node.js environment to detect and log the client's IANA time zone name.

const jstz = require('jstimezonedetect');

try {
  const tz = jstz.determine();
  console.log('Detected IANA Time Zone:', tz.name());
} catch (error) {
  console.error('Error detecting time zone:', error.message);
}