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World Congress 2026 Europe - Virtual Stage • Jul 2, 2026 • Session details

It's about time! The new Temporal API in JavaScript

Marco Sieben

Tired of JavaScript's unpredictable Date object? Discover how the new native Temporal API eliminates silent bugs and bulky libraries with immutable, type-safe time handling.

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#1 about 2 min

Overview of the JavaScript date and time ecosystem

Background on full-stack development and the historical limitations of managing times within JavaScript.

#2 about 11 min

Legacy JavaScript date API quirks and inconsistencies

The confusing instantiation behaviors, zero-based indexing, and mutability issues inherent in the legacy Date object.

#3 about 4 min

Core use cases for representing points in time

The distinction between exact points in history, timezone-aware events, and context-free plain dates.

#4 about 3 min

Drawbacks of third-party date handling libraries

The hidden costs of external dependencies like bundle bloat, security risks, and missing core primitives.

#5 about 2 min

Core architecture and design philosophy of Temporal

How the new API enforces immutability, type safety, fail-fast mechanics, and strict standard compliance.

#6 about 4 min

Standardization timeline and engine adoption history

The journey of the Temporal proposal through formal stages towards integration into the ECMAScript standard.

#7 about 2 min

Current browser compatibility and polyfill support

The ongoing implementation status across major browsers and backend runtime environments like Node and Deno.

#8 about 2 min

Mapping common application use cases to Temporal data types

The specific object classes used to represent instants, zoned dates, plain times, and precise durations.

#9 about 4 min

Code patterns for instantiating Temporal objects

Using factory methods and strict standard strings to construct precise time data representations programmatically.

#10 about 9 min

Strict parsing and fail-fast validation mechanics

Examples of how the API intentionally rejects ambiguous strings, mismatched timezones, and invalid historical offsets.

#11 about 3 min

Formatting output strings and standardizing localized UI displays

Converting objects back to standard representations and styling localized interface strings via native browser utilities.

#12 about 3 min

Modifying dates and calculating differences between Temporal instances

Safely adding durations, comparing values for sorting, and converting strictly between different discrete object types.

#13 about 3 min

Handling date edge cases and context-dependent timeline calculations

Why operations like adding raw days to absolute instants intentionally trigger strict validation errors.

#14 about 2 min

Integrating non-standard regional calendars into date calculations

Calculating accurate date differences when utilizing alternative regional calendars natively supported by modern browser environments.

#15 about 5 min

Evaluating performance and bundle size through library benchmarks

Benchmark measurements proving native standard interfaces dramatically improve execution speed and reduce application payload sizes.

#16 about 5 min

Incremental migration strategies for updating legacy codebase date logic

Best practices for implementing polyfills, migrating components selectively, and ensuring unit test data matches reality.

#17 about 3 min

Effort estimation and real-world application migration case study

A practical breakdown of replacing a legacy date library within a complex medium-sized software application.

#18 about 3 min

Remaining structural limitations and ongoing Temporal adoption gaps

Current structural challenges such as framework verbosity, missing utility operations, and absent loose parsing capabilities.

Matching moments

1:18 min

Adopting the Temporal API for JavaScript date management

Chris Heilmann +2 · LIVE

6:47 min

Handling complex date calculations with the Temporal API

Chris Heilmann +2 · LIVE

4:13 min

Replacing legacy date objects with the temporal application interface

Chris Heilmann +2 · LIVE

44 sec

Navigating legacy JavaScript date parsing inconsistencies

Chris Heilmann +3 · LIVE

2:46 min

Handling relative time formats and temporal formatting APIs

Chris Heilmann +2 · LIVE

1:37 min

Introducing durable execution and the Temporal framework

Geetha Anne · LIVE

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