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Locale-based localization (date / currency / language)

getLocale() returns a BCP 47 locale tag synchronously (e.g. 'ko-KR', 'en-US'). Combined with the standard Intl API, you can localize dates, currency, and numbers without an extra library.

Format dates and currency​

import { getLocale } from '@apps-in-toss/web-framework';

const locale = getLocale(); // e.g. 'ko-KR'

function formatDate(date: Date): string {
  return new Intl.DateTimeFormat(locale, {
    year: 'numeric',
    month: 'long',
    day: 'numeric',
  }).format(date);
}

function formatCurrency(amount: number, currency = 'KRW'): string {
  return new Intl.NumberFormat(locale, {
    style: 'currency',
    currency,
  }).format(amount);
}

// 'ko-KR' → '2024년 1월 14일', '₩1,000'
// 'en-US' → 'January 14, 2024', 'KRW 1,000'

Intl.DateTimeFormat and Intl.NumberFormat instances are reusable. Wrap them in useMemo if you have many renders.

Extract the language code and branch UI text​

import { getLocale } from '@apps-in-toss/web-framework';

const locale = getLocale();
const lang = locale.split('-')[0]; // 'ko', 'en', 'ja', …

const messages: Record<string, { greeting: string }> = {
  ko: { greeting: '안녕하세요' },
  en: { greeting: 'Hello' },
  ja: { greeting: 'こんにちは' },
};

function Greeting() {
  const { greeting } = messages[lang] ?? messages.ko;
  return <h1>{greeting}</h1>;
}

Extracting just the two-letter language prefix (lang) lets you branch by language independently of the region code (KR, US). Fall back to 'ko' for unsupported languages.

  • getLocale — returns the BCP 47 locale tag.
  • getPlatformOS — use alongside locale when date display conventions differ by platform.