ahbanavi · August 6, 2026 14:17
diff --git a/README.md b/README.md
diff --git a/webos-intl-timezone-fix.js b/webos-intl-timezone-fix.js
 /**
 * Fix clocks in the Jellyfin webOS (LG Smart TV) client showing the wrong time.
 *
 * PROBLEM
 *   Every clock jellyfin-web renders is off by exactly your UTC offset — the
 *   header clock next to the profile image, every "Ends at HH:MM" on media
 *   detail pages and in playback info. The TV's own time zone setting is
 *   correct, and so are the Jellyfin server's host and container time zones.
 *
 * CAUSE
 *   webOS's WebAppManager engine resolves the default Intl time zone to
 *   "Etc/Unknown", which ICU formats as UTC:
 *
 *     new Date().toString()             -> "... 17:35:52 GMT+0330 (+03:30)"   correct
 *     new Date().getHours()             -> 17                                 correct
 *     new Date().toLocaleTimeString()   -> "2:05:52 PM"                       UTC
 *     Intl.DateTimeFormat().resolvedOptions().timeZone -> "Etc/Unknown"
 *
 *   Date is fine; only Intl-based formatting is wrong. jellyfin-web renders
 *   every clock through Intl, so they all shift together.
 *
 * FIX
 *   Passing an explicit IANA zone formats correctly, so this pins the default
 *   zone by wrapping Intl.DateTimeFormat and the three Date.prototype
 *   toLocale*String methods.
 *
 * SAFETY
 *   Self-gating: it patches nothing unless the engine's own formatting
 *   disagrees with getHours() AND the configured zone matches the device's
 *   real local time. Healthy clients (desktop, phone, Android TV) are
 *   untouched, so it is safe to apply server-wide.
 *
 * SETUP
 *   Set TIME_ZONE below to your IANA zone, e.g. "Europe/Berlin",
 *   "America/New_York", "Asia/Tehran". It cannot be auto-detected — the
 *   engine's inability to report it is the bug being worked around.
 */
 (function () {
    'use strict';

    // ---- CHANGE THIS to your IANA time zone -------------------------------
    var TIME_ZONE = 'Asia/Tehran';
    // -----------------------------------------------------------------------

    if (window.__webosIntlTimeZonePatched) {
        return;
    }

    var NativeDateTimeFormat = Intl.DateTimeFormat;
    var nativeToLocaleString = Date.prototype.toLocaleString;
    var nativeToLocaleTimeString = Date.prototype.toLocaleTimeString;
    var nativeToLocaleDateString = Date.prototype.toLocaleDateString;

    /** Hour that Intl renders for `date`, in `zone` (omit zone for the engine default). */
    function formattedHour(date, zone) {
        var options = { hour: '2-digit', hour12: false };
        if (zone) {
            options.timeZone = zone;
        }
        var hour = parseInt(new NativeDateTimeFormat('en-GB', options).format(date), 10);
        return hour === 24 ? 0 : hour; // en-GB renders midnight as "24"
    }

    var now = new Date();

    try {
        // Healthy engine: Intl's default zone already agrees with the clock. Nothing to do.
        if (formattedHour(now) === now.getHours()) {
            return;
        }
        // Only pin a zone that actually matches this device's real local time, so a
        // client in some other zone is never forced onto TIME_ZONE.
        if (formattedHour(now, TIME_ZONE) !== now.getHours()) {
            return;
        }
    } catch (err) {
        return; // Can't tell what the engine is doing — leave it alone.
    }

    function withZone(options) {
        var merged = {};
        if (options) {
            for (var key in options) {
                if (Object.prototype.hasOwnProperty.call(options, key)) {
                    merged[key] = options[key];
                }
            }
        }
        if (!merged.timeZone) {
            merged.timeZone = TIME_ZONE;
        }
        return merged;
    }

    function PatchedDateTimeFormat(locales, options) {
        return new NativeDateTimeFormat(locales, withZone(options));
    }
    PatchedDateTimeFormat.prototype = NativeDateTimeFormat.prototype;
    PatchedDateTimeFormat.supportedLocalesOf = function (locales, options) {
        return NativeDateTimeFormat.supportedLocalesOf(locales, options);
    };
    Intl.DateTimeFormat = PatchedDateTimeFormat;

    // Invalid locales must still throw RangeError here — jellyfin-web's
    // datetime.js feature-detects localization support with toLocaleTimeString('i').
    Date.prototype.toLocaleString = function (locales, options) {
        return nativeToLocaleString.call(this, locales, withZone(options));
    };
    Date.prototype.toLocaleTimeString = function (locales, options) {
        return nativeToLocaleTimeString.call(this, locales, withZone(options));
    };
    Date.prototype.toLocaleDateString = function (locales, options) {
        return nativeToLocaleDateString.call(this, locales, withZone(options));
    };

    window.__webosIntlTimeZonePatched = TIME_ZONE;
    console.log('[webos-tz] Intl default zone was unusable; pinned formatting to ' + TIME_ZONE);
 })();
App	User-Agent	`Intl` default zone	`toLocaleTimeString()`
Web Browser	`...(Linux; NetCast; U)... Colt/2.0`	`undefined`	✅ correct local time
Jellyfin (and other web apps)	`...(Web0S; Linux/SmartTV)... WebAppManager`	`Etc/Unknown`	❌ UTC
	before	after
`toLocaleTimeString()`	`2:05:52 PM` ❌	`5:40:12 PM` ✅
`Intl…resolvedOptions().timeZone`	`Etc/Unknown`	`Asia/Tehran` ✅
`__webosIntlTimeZonePatched`	`undefined`	`Asia/Tehran`
	/**
	* Fix clocks in the Jellyfin webOS (LG Smart TV) client showing the wrong time.
	*
	* PROBLEM
	* Every clock jellyfin-web renders is off by exactly your UTC offset — the
	* header clock next to the profile image, every "Ends at HH:MM" on media
	* detail pages and in playback info. The TV's own time zone setting is
	* correct, and so are the Jellyfin server's host and container time zones.
	*
	* CAUSE
	* webOS's WebAppManager engine resolves the default Intl time zone to
	* "Etc/Unknown", which ICU formats as UTC:
	*
	* new Date().toString() -> "... 17:35:52 GMT+0330 (+03:30)" correct
	* new Date().getHours() -> 17 correct
	* new Date().toLocaleTimeString() -> "2:05:52 PM" UTC
	* Intl.DateTimeFormat().resolvedOptions().timeZone -> "Etc/Unknown"
	*
	* Date is fine; only Intl-based formatting is wrong. jellyfin-web renders
	* every clock through Intl, so they all shift together.
	*
	* FIX
	* Passing an explicit IANA zone formats correctly, so this pins the default
	* zone by wrapping Intl.DateTimeFormat and the three Date.prototype
	* toLocale*String methods.
	*
	* SAFETY
	* Self-gating: it patches nothing unless the engine's own formatting
	* disagrees with getHours() AND the configured zone matches the device's
	* real local time. Healthy clients (desktop, phone, Android TV) are
	* untouched, so it is safe to apply server-wide.
	*
	* SETUP
	* Set TIME_ZONE below to your IANA zone, e.g. "Europe/Berlin",
	* "America/New_York", "Asia/Tehran". It cannot be auto-detected — the
	* engine's inability to report it is the bug being worked around.
	*/
	(function () {
	'use strict';

	// ---- CHANGE THIS to your IANA time zone -------------------------------
	var TIME_ZONE = 'Asia/Tehran';
	// -----------------------------------------------------------------------

	if (window.__webosIntlTimeZonePatched) {
	return;
	}

	var NativeDateTimeFormat = Intl.DateTimeFormat;
	var nativeToLocaleString = Date.prototype.toLocaleString;
	var nativeToLocaleTimeString = Date.prototype.toLocaleTimeString;
	var nativeToLocaleDateString = Date.prototype.toLocaleDateString;

	/** Hour that Intl renders for `date`, in `zone` (omit zone for the engine default). */
	function formattedHour(date, zone) {
	var options = { hour: '2-digit', hour12: false };
	if (zone) {
	options.timeZone = zone;
	}
	var hour = parseInt(new NativeDateTimeFormat('en-GB', options).format(date), 10);
	return hour === 24 ? 0 : hour; // en-GB renders midnight as "24"
	}

	var now = new Date();

	try {
	// Healthy engine: Intl's default zone already agrees with the clock. Nothing to do.
	if (formattedHour(now) === now.getHours()) {
	return;
	}
	// Only pin a zone that actually matches this device's real local time, so a
	// client in some other zone is never forced onto TIME_ZONE.
	if (formattedHour(now, TIME_ZONE) !== now.getHours()) {
	return;
	}
	} catch (err) {
	return; // Can't tell what the engine is doing — leave it alone.
	}

	function withZone(options) {
	var merged = {};
	if (options) {
	for (var key in options) {
	if (Object.prototype.hasOwnProperty.call(options, key)) {
	merged[key] = options[key];
	}
	}
	}
	if (!merged.timeZone) {
	merged.timeZone = TIME_ZONE;
	}
	return merged;
	}

	function PatchedDateTimeFormat(locales, options) {
	return new NativeDateTimeFormat(locales, withZone(options));
	}
	PatchedDateTimeFormat.prototype = NativeDateTimeFormat.prototype;
	PatchedDateTimeFormat.supportedLocalesOf = function (locales, options) {
	return NativeDateTimeFormat.supportedLocalesOf(locales, options);
	};
	Intl.DateTimeFormat = PatchedDateTimeFormat;

	// Invalid locales must still throw RangeError here — jellyfin-web's
	// datetime.js feature-detects localization support with toLocaleTimeString('i').
	Date.prototype.toLocaleString = function (locales, options) {
	return nativeToLocaleString.call(this, locales, withZone(options));
	};
	Date.prototype.toLocaleTimeString = function (locales, options) {
	return nativeToLocaleTimeString.call(this, locales, withZone(options));
	};
	Date.prototype.toLocaleDateString = function (locales, options) {
	return nativeToLocaleDateString.call(this, locales, withZone(options));
	};

	window.__webosIntlTimeZonePatched = TIME_ZONE;
	console.log('[webos-tz] Intl default zone was unusable; pinned formatting to ' + TIME_ZONE);
	})();