A 50-year accident: how JavaScript got Date, and why Temporal exists
summary
JavaScript Date is a single mutable number representing milliseconds since 1970 so it exposes only UTC or the host zone, yields off‑by‑one months, and forces ad hoc workarounds. Temporal adds a new, immutable set of types — Instant, PlainDateTime, ZonedDateTime, Duration — separating epoch time, wall clock dates, zones and durations. The proposal spends nine years to land in ECMAScript 2026 and Node 26, depends on the IANA tzdb for correctness, and already fixes most common calendar and DST failure modes.
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chapters (8)
- 0:00Introduction
- 1:54JavaScript Date problems
- 4:46Unix time limitations
- 7:15Time zones maintenance
- 9:07Java’s mutable Date
- 11:18Moment.js rise and fall
- 12:45Temporal API proposal
- 15:23Temporal adoption challenges
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