nl_tokens: Compares a BCP 47 language priority list requestedLocales against the locales in availableLocales and determines the best available language to meet the request . Two algorithms are available to match the locales : the Lookup algorithm described in RFC 4647 section 3 . 4 and an implementation dependent best - fit algorithm . Independent of the locale matching algorithm options specified through Unicode locale extension sequences are negotiated separately taking the caller s relevant extension keys and locale data as well as client - provided options into consideration . Returns an object with a locale property whose value is the language tag of the selected locale and properties for each key in relevantExtensionKeys providing the selected value for that key .
pl_tokens: function resolveLocale ( <mask> , requestedLocales , options ) { requestedLocales = initializeLocaleList ( requestedLocales ) ; var getOption = getGetOption ( options , service ) ; var matcher = getOption ( 'localeMatcher' , 'string' , [ 'lookup' , 'best fit' ] , 'best fit' ) ; var resolved ; if ( matcher === 'lookup' ) { resolved = lookupMatcher ( service , requestedLocales ) ; } else { resolved = bestFitMatcher ( service , requestedLocales ) ; } return resolved ; }