Temporal API Migration Analysis

This document captures the analysis of migrating from Luxon to the JavaScript Temporal API.

Research

• https://github.com/tc39/proposal-temporal
• https://tc39.es/proposal-temporal/docs/
• https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Temporal
• https://github.com/js-temporal/temporal-polyfill
• https://github.com/fullcalendar/temporal-polyfill

Current State (May 2025)

Luxon Usage:

• 8 files import Luxon for datetime operations
• Heavy timezone handling: GPS inference, UTC offsets, DST adjustments
• Custom "UnsetZone" workaround for unspecified timezones
• Bundle: ~66KB (20KB gzipped)

Temporal Status:

• Still experimental (Stage 3)
• Neither polyfills are production-ready
• Polyfill bundle: ~200KB (50KB gzipped) vs Luxon's 66KB (20KB gzipped)

Migration

Prerequisites

• [ ] Temporal reaches Stage 4
• [ ] Polyfill is production-ready
• [ ] Performance validation vs Luxon

Note: Waiting for stable Node.js native support will take years after browsers ship

Step 1: Add Temporal output methods alongside Luxon

// In ExifDateTime.ts
toZonedDateTime(): Temporal.ZonedDateTime
toPlainDateTime(): Temporal.PlainDateTime
static fromZonedDateTime(zdt: Temporal.ZonedDateTime): ExifDateTime
Copy

Benefits: No breaking changes, user choice, easy adoption path

Downsides: This would require us to add a dependency on one of the polyfills

Step 2: deprecate luxon output methods

Step 3: major release, remove luxon