Function normalizeZone

normalizeZone(input: unknown): Maybe<Zone<boolean>>

Normalize a timezone input to a valid Luxon Zone.

Accepts multiple input formats and returns a validated Zone instance, or undefined if the input cannot be normalized to a valid timezone.

Supported input formats:

Numbers: Timezone offset in minutes (e.g., 480 = UTC+8, -300 = UTC-5)
Strings: ISO offsets ("+08:00", "-05:00"), IANA zones ("America/Los_Angeles"), UTC variants ("UTC", "GMT", "Z", "Zulu")
Zone instances: Validated and returned if valid

The function respects Settings:

Settings.allowArchaicTimezoneOffsets for pre-1982 offsets
Settings.allowBakerIslandTime for UTC-12:00

Parameters

input: unknown
Timezone in various formats

Returns Maybe<Zone<boolean>>

Valid Zone instance, or undefined if invalid

Example

// Numbers (offset in minutes)
normalizeZone(480)?.name     // "UTC+8"
normalizeZone(-300)?.name    // "UTC-5"
normalizeZone(0)?.name       // "UTC"

// ISO offset strings
normalizeZone("+08:00")?.name      // "UTC+8"
normalizeZone("-05:30")?.name      // "UTC-5:30"
normalizeZone("UTC+7")?.name       // "UTC+7"

// IANA timezone names
normalizeZone("America/Los_Angeles")?.name  // "America/Los_Angeles"
normalizeZone("Asia/Tokyo")?.name           // "Asia/Tokyo"

// UTC aliases
normalizeZone("UTC")?.name   // "UTC"
normalizeZone("GMT")?.name   // "UTC"
normalizeZone("Z")?.name     // "UTC"
normalizeZone("Zulu")?.name  // "UTC"

// Invalid inputs return undefined
normalizeZone("invalid")     // undefined
normalizeZone("+25:00")      // undefined (beyond ±14 hours)
normalizeZone(1200)          // undefined (20 hours, beyond ±14 hours)
normalizeZone(100)           // undefined (not a valid timezone offset)
normalizeZone(-1)            // undefined (UnsetZone sentinel)
normalizeZone(null)          // undefined