swift-formatstyle

Format Swift values for display using the FormatStyle protocol.

Updated Apr 30, 2026
One-click install
npx skills add https://github.com/onymchat/onym-ios --skill swift-formatstyle
Or copy as Structured Prompt for Agent
Please help me install this Agent Skill.
Skill: swift-formatstyle
Source: https://github.com/onymchat/onym-ios/tree/main/.claude/skills/swift-formatstyle
Command: npx skills add https://github.com/onymchat/onym-ios --skill swift-formatstyle

SYSTEM DOCUMENTATION & REQUIREMENTS

What problem does it solve?

Formatting values for display is a common task that benefits from a modern, type-safe approach. This skill enables developers to present numbers, currencies, percentages, dates, durations, measurements, and more in a human-friendly way using Swift's FormatStyle protocol, ensuring locale-aware and consistent output across UI components.

Core Features & Use Cases

  • Formats numbers, currencies, percentages, dates, durations, measurements, and names using concrete FormatStyle types.
  • Supports composition and localization to produce consistent UI strings in SwiftUI and UIKit applications.
  • Allows creating custom FormatStyle conformances for domain-specific formatting and reusable logic across an app.

Quick Start

Format a sample value using a FormatStyle to see the resulting string.

Frequently Asked Questions about swift-formatstyle

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I format dates and numbers for human-readable display in Swift?

Use Swift FormatStyle to format values like dates, numbers, and currencies for human-readable display. It applies locale-aware formatting to produce consistent UI strings across SwiftUI and UIKit applications using type-safe configurations.

What is the best way to format currencies and measurements in iOS 15+?

Swift FormatStyle is the best approach for formatting currencies and measurements in iOS 15+, providing type-safe, composable style configurations that replace legacy formatters and improve performance with locale-aware output.

Can I create custom FormatStyle conformances for domain-specific formatting in Swift?

Yes, you can create custom FormatStyle conformances for domain-specific formatting in Swift. This allows you to build reusable formatting logic that integrates seamlessly with SwiftUI and produces consistent localized strings.

How does Swift FormatStyle compare to legacy formatters like NumberFormatter?

Swift FormatStyle replaces legacy formatters like NumberFormatter by offering type-safe, composable configurations that improve performance. It enables locale-aware formatting for numbers, dates, and durations without the overhead of legacy objects.

Do I need iOS 15 to use Swift FormatStyle for locale-aware string formatting?

Yes, Swift FormatStyle requires iOS 15 or later to format values with locale-aware string output. It leverages modern Foundation protocols to provide type-safe formatting for numbers, dates, currencies, and measurements.

Why should I use FormatStyle instead of string interpolation for displaying percentages in SwiftUI?

FormatStyle provides locale-aware, type-safe formatting for displaying percentages in SwiftUI, replacing error-prone string interpolation. It ensures consistent human-readable output across different regions by using composable style configurations.