How are timezones handled in version 4?

Version 4 uses the @date-fns/tz package and the TZDate class, which allows for timezone-aware date operations without the overhead of older libraries.

Does it support internationalization (i18n)?

Yes, it includes patterns for locale-aware formatting shortcuts (P, PP, PPP) that automatically adapt date formats to the user's region.

How does this skill help with bundle size optimization?

The skill enforces modular imports (e.g., importing { format } from 'date-fns') rather than the entire library, allowing modern bundlers to tree-shake unused code.

Why use date-fns over the native Date object?

Native Date objects are mutable and their string parsing is inconsistent across browsers. date-fns provides pure, predictable functions and reliable parsing via parseISO.

Date Utility Patterns (date-fns)

Name: Date Utility Patterns (date-fns)
Author: agents-inc

byagents-inc

0•

開発者ツール

Implements high-performance, tree-shakeable date manipulation and formatting patterns using date-fns for TypeScript applications.

This skill provides specialized guidance for using date-fns, a modular and functional date utility library, within TypeScript environments. It enforces best practices such as safe parsing with parseISO, immutable date arithmetic, and locale-aware formatting while preventing common anti-patterns like manual date mutation or browser-inconsistent date constructors. By focusing on tree-shaking and pure functions, it helps developers build performant, bug-free date logic for web applications, including complex timezone handling with v4 TZDate and internationalization support.

主な機能

01Safe ISO 8601 parsing and validation to prevent browser-specific inconsistencies

02Standardized formatting using Unicode tokens and locale-aware shortcuts

03Immutable date arithmetic for predictable and side-effect-free state management

04Tree-shakeable import patterns to minimize production bundle sizes

05Advanced timezone and DST handling using @date-fns/tz and TZDate

060 GitHub stars

ユースケース

01Building localized calendar interfaces and date-range pickers

02Transforming server-side ISO timestamps into user-friendly localized displays

03Calculating subscription billing cycles and trial period expirations

What are Skills?·How to Install

Install with 🐟 Skill.Fish

npx skillfish add agents-inc/skills web-utilities-date-fns

For use in Claude.ai and ChatGPT

Download Skill