fluent-core-langneg

Language negotiation matches user preferred locales against available app locales using strategies like filtering, matching, and lookup to build a suitable negotiated locale order. It ensures users receive content in the best matching language.

acceptedLanguages parses HTTP Accept-Language headers to extract and apply BCP47 locale tags. It uses subtag matching to construct precise fallback chains for server-side localization contexts.

Filtering returns all matching locales, matching finds the best specific fits, and lookup selects a single default locale when exact matches fail. These strategies dictate how locale fallback orders are constructed.

Yes, it provides a complete workflow for both client-side and server-side localization. It constructs consistent fallback chains and handles edge cases with strict input validation across both contexts.

The lookup strategy requires a defaultLocale to guarantee a valid return value when no user preferred locales match the available app locales. It ensures the application always resolves to a functional language.

BCP47 subtag matching constructs precise fallbacks but may hit edge cases requiring strict input validation. It relies on consistent API behavior to prevent incorrect strategy choices and broken user experiences.