42 lines
1.2 KiB
TypeScript
42 lines
1.2 KiB
TypeScript
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/** Helpers for displaying geo database keys. */
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const displayNames = new Map<string, Intl.DisplayNames>()
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function names(lang: string): Intl.DisplayNames | null {
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const locale = lang === 'zh' ? 'zh-CN' : 'en'
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if (!displayNames.has(locale)) {
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try {
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displayNames.set(locale, new Intl.DisplayNames([locale], { type: 'region' }))
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} catch {
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return null
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}
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}
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return displayNames.get(locale) ?? null
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}
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/**
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* Localized country name for a two letter code, or null when the code is not a
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* country. GeoIP databases also contain provider groups such as "cloudflare".
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*/
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export function regionName(code: string, lang: string): string | null {
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if (!/^[a-z]{2}$/i.test(code)) return null
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const upper = code.toUpperCase()
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try {
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const name = names(lang)?.of(upper)
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return name && name !== upper ? name : null
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} catch {
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return null
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}
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}
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/** Flag emoji for a two letter country code, empty for anything else. */
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export function flagOf(code: string): string {
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if (!/^[a-z]{2}$/i.test(code)) return ''
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const base = 0x1f1e6
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const upper = code.toUpperCase()
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return String.fromCodePoint(
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base + upper.charCodeAt(0) - 65,
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base + upper.charCodeAt(1) - 65,
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)
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}
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