snapshot of https://github.com/tldraw/tldraw.git (main, 2026-09-23; blobs > 131072B omitted)

packages/tlschema/src/translations/translations.test.ts

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+import { afterEach, describe, expect, it, vi } from 'vitest'
+import {
+	LANGUAGES,
+	TLLanguage,
+	_getDefaultTranslationLocale,
+	getDefaultTranslationLocale,
+} from './translations'
+
+interface DefaultLanguageTest {
+	name: string
+	input: string[]
+	output: string
+}
+
+const originalWindow = global.window
+
+describe('translations.ts', () => {
+	describe('exports', () => {
+		it('should export LANGUAGES constant', () => {
+			expect(LANGUAGES).toBeDefined()
+			expect(Array.isArray(LANGUAGES)).toBe(true)
+			expect(LANGUAGES.length).toBeGreaterThan(0)
+		})
+
+		it('should export TLLanguage type', () => {
+			// Test that TLLanguage type works correctly
+			const testLanguage: TLLanguage = LANGUAGES[0]
+			expect(testLanguage).toHaveProperty('locale')
+			expect(testLanguage).toHaveProperty('label')
+			expect(typeof testLanguage.locale).toBe('string')
+			expect(typeof testLanguage.label).toBe('string')
+		})
+
+		it('should export getDefaultTranslationLocale function', () => {
+			expect(typeof getDefaultTranslationLocale).toBe('function')
+		})
+
+		it('should export _getDefaultTranslationLocale function', () => {
+			expect(typeof _getDefaultTranslationLocale).toBe('function')
+		})
+	})
+
+	describe('getDefaultTranslationLocale', () => {
+		afterEach(() => {
+			// Restore original window
+			global.window = originalWindow
+			vi.clearAllMocks()
+		})
+
+		it('should return default locale in browser environment', () => {
+			// Mock browser environment
+			global.window = {
+				navigator: {
+					languages: ['fr', 'en'],
+				},
+			} as any
+
+			const locale = getDefaultTranslationLocale()
+			expect(locale).toBe('fr')
+		})
+
+		it('should use navigator.languages when available', () => {
+			// Mock browser environment with navigator.languages
+			global.window = {
+				navigator: {
+					languages: ['de', 'es', 'en'],
+				},
+			} as any
+
+			const locale = getDefaultTranslationLocale()
+			expect(locale).toBe('de')
+		})
+
+		it('should fallback to English when navigator.languages is null/undefined', () => {
+			// Mock browser environment with null languages
+			global.window = {
+				navigator: {
+					languages: null,
+				},
+			} as any
+
+			const locale = getDefaultTranslationLocale()
+			expect(locale).toBe('en')
+		})
+
+		it('should return English in server environment (no window)', () => {
+			// Mock server environment
+			delete (global as any).window
+
+			const locale = getDefaultTranslationLocale()
+			expect(locale).toBe('en')
+		})
+
+		it('should handle undefined navigator gracefully', () => {
+			// Mock browser environment without navigator
+			global.window = {
+				navigator: undefined,
+			} as any
+
+			const locale = getDefaultTranslationLocale()
+			expect(locale).toBe('en')
+		})
+
+		it('should handle empty languages array', () => {
+			// Mock browser environment with empty languages array
+			global.window = {
+				navigator: {
+					languages: [],
+				},
+			} as any
+
+			const locale = getDefaultTranslationLocale()
+			expect(locale).toBe('en')
+		})
+
+		it('should work with complex browser language preferences', () => {
+			// Test realistic browser scenario
+			global.window = {
+				navigator: {
+					languages: ['zh-TW', 'zh', 'en-US', 'en'],
+				},
+			} as any
+
+			const locale = getDefaultTranslationLocale()
+			expect(locale).toBe('zh-tw') // Should match zh-TW exactly
+		})
+	})
+
+	describe('_getDefaultTranslationLocale (internal logic)', () => {
+		const tests: DefaultLanguageTest[] = [
+			{
+				name: 'finds a matching language locale',
+				input: ['fr'],
+				output: 'fr',
+			},
+			{
+				name: 'finds a matching region locale',
+				input: ['pt-PT'],
+				output: 'pt-pt',
+			},
+			{
+				name: 'picks a region locale if no language locale available',
+				input: ['pt'],
+				output: 'pt-br',
+			},
+			{
+				name: 'picks a language locale if no region locale available',
+				input: ['fr-CA'],
+				output: 'fr',
+			},
+			{
+				name: 'picks the first language that loosely matches',
+				input: ['fr-CA', 'pt-PT'],
+				output: 'fr',
+			},
+		]
+
+		for (const test of tests) {
+			it(test.name, () => {
+				expect(_getDefaultTranslationLocale(test.input)).toEqual(test.output)
+			})
+		}
+
+		it('should return "en" when no locales provided', () => {
+			expect(_getDefaultTranslationLocale([])).toBe('en')
+		})
+
+		it('should return "en" when no supported locales found', () => {
+			expect(_getDefaultTranslationLocale(['xyz', 'abc', 'unknown'])).toBe('en')
+		})
+
+		it('should handle case insensitive matching', () => {
+			expect(_getDefaultTranslationLocale(['FR'])).toBe('fr')
+			expect(_getDefaultTranslationLocale(['PT-BR'])).toBe('pt-br')
+			expect(_getDefaultTranslationLocale(['ZH-CN'])).toBe('zh-cn')
+		})
+
+		it('should handle mixed case and separators', () => {
+			expect(_getDefaultTranslationLocale(['pt_BR'])).toBe('pt-br')
+			expect(_getDefaultTranslationLocale(['zh_CN'])).toBe('zh-cn')
+			expect(_getDefaultTranslationLocale(['KO_KR'])).toBe('ko-kr')
+		})
+
+		it('should prioritize exact matches over fallbacks', () => {
+			expect(_getDefaultTranslationLocale(['pt-pt', 'pt'])).toBe('pt-pt')
+			expect(_getDefaultTranslationLocale(['zh-tw', 'zh'])).toBe('zh-tw')
+		})
+
+		it('should handle default region assignments correctly', () => {
+			// Chinese defaults to zh-cn
+			expect(_getDefaultTranslationLocale(['zh'])).toBe('zh-cn')
+			// Portuguese defaults to pt-br
+			expect(_getDefaultTranslationLocale(['pt'])).toBe('pt-br')
+			// Korean defaults to ko-kr
+			expect(_getDefaultTranslationLocale(['ko'])).toBe('ko-kr')
+			// Hindi defaults to hi-in
+			expect(_getDefaultTranslationLocale(['hi'])).toBe('hi-in')
+		})
+
+		it('should handle region-to-language fallback', () => {
+			// fr-CA should fallback to fr (if we only have generic French)
+			expect(_getDefaultTranslationLocale(['fr-CA'])).toBe('fr')
+			// es-MX should fallback to es
+			expect(_getDefaultTranslationLocale(['es-MX'])).toBe('es')
+		})
+
+		it('should respect locale priority order', () => {
+			// First supported locale should win
+			expect(_getDefaultTranslationLocale(['unsupported', 'fr', 'de'])).toBe('fr')
+			expect(_getDefaultTranslationLocale(['xyz', 'de', 'fr'])).toBe('de')
+		})
+
+		it('should handle complex regional scenarios', () => {
+			// zh-HK not supported, should fallback to default zh-cn (doesn't continue to next locale)
+			expect(_getDefaultTranslationLocale(['zh-HK', 'zh-TW', 'en'])).toBe('zh-cn')
+			// zh-SG not supported, should fallback to default zh-cn
+			expect(_getDefaultTranslationLocale(['zh-SG', 'zh-CN', 'en'])).toBe('zh-cn')
+			// Test exact match takes priority
+			expect(_getDefaultTranslationLocale(['zh-TW', 'zh-CN'])).toBe('zh-tw')
+			// Test fallback behavior
+			expect(_getDefaultTranslationLocale(['zh-HK', 'zh'])).toBe('zh-cn')
+		})
+
+		it('should work with single locale array', () => {
+			expect(_getDefaultTranslationLocale(['fr'])).toBe('fr')
+			expect(_getDefaultTranslationLocale(['unsupported'])).toBe('en')
+		})
+
+		it('should handle whitespace and malformed locales gracefully', () => {
+			// These should not crash but return fallback
+			expect(_getDefaultTranslationLocale([' '])).toBe('en')
+			expect(_getDefaultTranslationLocale([''])).toBe('en')
+			// Malformed locales should fallback to English when they can't be parsed properly
+			expect(_getDefaultTranslationLocale(['fr-'])).toBe('en')
+			// But valid partial matches should work
+			expect(_getDefaultTranslationLocale(['fr', 'en'])).toBe('fr')
+		})
+	})
+
+	describe('getSupportedLocale (internal function behavior)', () => {
+		// Note: getSupportedLocale is not exported, but we can test its behavior through _getDefaultTranslationLocale
+		it('should find exact locale matches', () => {
+			// These test the internal getSupportedLocale logic through the public API
+			expect(_getDefaultTranslationLocale(['en'])).toBe('en')
+			expect(_getDefaultTranslationLocale(['fr'])).toBe('fr')
+			expect(_getDefaultTranslationLocale(['pt-br'])).toBe('pt-br')
+		})
+
+		it('should handle case normalization in exact matches', () => {
+			expect(_getDefaultTranslationLocale(['EN'])).toBe('en')
+			expect(_getDefaultTranslationLocale(['PT-BR'])).toBe('pt-br')
+			expect(_getDefaultTranslationLocale(['ZH-TW'])).toBe('zh-tw')
+		})
+
+		it('should fall back from region to language', () => {
+			// fr-CA -> fr (assuming we have generic French)
+			expect(_getDefaultTranslationLocale(['fr-CA'])).toBe('fr')
+			// es-AR -> es
+			expect(_getDefaultTranslationLocale(['es-AR'])).toBe('es')
+		})
+
+		it('should assign default regions for base languages', () => {
+			// zh -> zh-cn (default Chinese region)
+			expect(_getDefaultTranslationLocale(['zh'])).toBe('zh-cn')
+			// pt -> pt-br (default Portuguese region)
+			expect(_getDefaultTranslationLocale(['pt'])).toBe('pt-br')
+		})
+
+		it('should return null for unsupported languages (via fallback to en)', () => {
+			// Unsupported languages should result in English fallback
+			expect(_getDefaultTranslationLocale(['xyz'])).toBe('en')
+			expect(_getDefaultTranslationLocale(['unsupported-locale'])).toBe('en')
+		})
+	})
+
+	describe('DEFAULT_LOCALE_REGIONS behavior', () => {
+		it('should apply Chinese default region correctly', () => {
+			expect(_getDefaultTranslationLocale(['zh'])).toBe('zh-cn')
+		})
+
+		it('should apply Portuguese default region correctly', () => {
+			expect(_getDefaultTranslationLocale(['pt'])).toBe('pt-br')
+		})
+
+		it('should apply Korean default region correctly', () => {
+			expect(_getDefaultTranslationLocale(['ko'])).toBe('ko-kr')
+		})
+
+		it('should apply Hindi default region correctly', () => {
+			expect(_getDefaultTranslationLocale(['hi'])).toBe('hi-in')
+		})
+
+		it('should not affect languages without default regions', () => {
+			// Languages like French, Spanish, German don't have default regions
+			expect(_getDefaultTranslationLocale(['fr'])).toBe('fr')
+			expect(_getDefaultTranslationLocale(['es'])).toBe('es')
+			expect(_getDefaultTranslationLocale(['de'])).toBe('de')
+		})
+	})
+
+	describe('TLLanguage type integration', () => {
+		it('should work correctly with TypeScript type system', () => {
+			// Test that return values match the TLLanguage locale type
+			const result: TLLanguage['locale'] = _getDefaultTranslationLocale(['fr'])
+			expect(result).toBe('fr')
+		})
+
+		it('should be compatible with LANGUAGES array', () => {
+			const allLocales: TLLanguage['locale'][] = LANGUAGES.map((lang) => lang.locale)
+
+			// Every result should be a valid locale from LANGUAGES
+			const testLocales = ['fr', 'pt-br', 'zh-cn', 'unsupported']
+			for (const locale of testLocales) {
+				const result = _getDefaultTranslationLocale([locale])
+				expect(allLocales).toContain(result)
+			}
+		})
+	})
+
+	describe('edge cases and robustness', () => {
+		it('should handle null and undefined inputs gracefully', () => {
+			// These should not crash the function
+			expect(() => _getDefaultTranslationLocale([] as any)).not.toThrow()
+			expect(_getDefaultTranslationLocale([])).toBe('en')
+		})
+
+		it('should handle very large locale arrays', () => {
+			const manyLocales = Array.from({ length: 1000 }, (_, i) => `lang-${i}`).concat(['fr']) // Add a valid one at the end
+
+			expect(_getDefaultTranslationLocale(manyLocales)).toBe('fr')
+		})
+
+		it('should handle special characters in locale strings', () => {
+			// Should not crash on malformed input
+			expect(() => _getDefaultTranslationLocale(['@#$%', 'fr'])).not.toThrow()
+			expect(_getDefaultTranslationLocale(['@#$%', 'fr'])).toBe('fr')
+		})
+
+		it('should handle extremely long locale strings', () => {
+			const longLocale = 'a'.repeat(1000)
+			expect(() => _getDefaultTranslationLocale([longLocale, 'fr'])).not.toThrow()
+			expect(_getDefaultTranslationLocale([longLocale, 'fr'])).toBe('fr')
+		})
+
+		it('should be consistent across multiple calls', () => {
+			const input = ['de', 'fr', 'es']
+			const result1 = _getDefaultTranslationLocale(input)
+			const result2 = _getDefaultTranslationLocale(input)
+			const result3 = _getDefaultTranslationLocale([...input]) // Spread to ensure different array
+
+			expect(result1).toBe(result2)
+			expect(result2).toBe(result3)
+			expect(result1).toBe('de')
+		})
+	})
+
+	describe('real-world usage scenarios', () => {
+		it('should handle typical browser language lists', () => {
+			// Common browser scenarios
+			expect(_getDefaultTranslationLocale(['en-US', 'en'])).toBe('en')
+			expect(_getDefaultTranslationLocale(['es-ES', 'es', 'en'])).toBe('es')
+			expect(_getDefaultTranslationLocale(['fr-FR', 'fr', 'en-US', 'en'])).toBe('fr')
+		})
+
+		it('should work for mobile browser scenarios', () => {
+			// iOS Safari typical format
+			expect(_getDefaultTranslationLocale(['zh-Hans-CN', 'zh-Hans', 'zh'])).toBe('zh-cn')
+			// Android Chrome typical format
+			expect(_getDefaultTranslationLocale(['pt-BR', 'pt', 'en-US'])).toBe('pt-br')
+		})
+
+		it('should handle multilingual user preferences', () => {
+			// User who speaks multiple languages
+			expect(_getDefaultTranslationLocale(['de-CH', 'fr-CH', 'it-CH', 'en'])).toBe('de')
+			expect(_getDefaultTranslationLocale(['es-MX', 'en-US', 'fr'])).toBe('es')
+		})
+
+		it('should work in internationalization scenarios', () => {
+			// Various international format inputs
+			expect(_getDefaultTranslationLocale(['ja-JP'])).toBe('ja')
+			expect(_getDefaultTranslationLocale(['ko-KR'])).toBe('ko-kr')
+			expect(_getDefaultTranslationLocale(['ar-SA'])).toBe('ar')
+			expect(_getDefaultTranslationLocale(['hi-IN'])).toBe('hi-in')
+		})
+	})
+})