get-user-locale/dist/index.js

Returns a list of strings representing the user's preferred languages.

import memoize from 'memoize';
function isString(el) {
    return typeof el === 'string';
}
function isUnique(el, index, arr) {
    return arr.indexOf(el) === index;
}
function isAllLowerCase(el) {
    return el.toLowerCase() === el;
}
function fixCommas(el) {
    return el.indexOf(',') === -1 ? el : el.split(',');
}
function normalizeLocale(locale) {
    if (!locale) {
        return locale;
    }
    if (locale === 'C' || locale === 'posix' || locale === 'POSIX') {
        return 'en-US';
    }
    // If there's a dot (.) in the locale, it's likely in the format of "en-US.UTF-8", so we only take the first part
    if (locale.indexOf('.') !== -1) {
        var _a = locale.split('.')[0], actualLocale = _a === void 0 ? '' : _a;
        return normalizeLocale(actualLocale);
    }
    // If there's an at sign (@) in the locale, it's likely in the format of "en-US@posix", so we only take the first part
    if (locale.indexOf('@') !== -1) {
        var _b = locale.split('@')[0], actualLocale = _b === void 0 ? '' : _b;
        return normalizeLocale(actualLocale);
    }
    // If there's a dash (-) in the locale and it's not all lower case, it's already in the format of "en-US", so we return it
    if (locale.indexOf('-') === -1 || !isAllLowerCase(locale)) {
        return locale;
    }
    var _c = locale.split('-'), splitEl1 = _c[0], _d = _c[1], splitEl2 = _d === void 0 ? '' : _d;
    return "".concat(splitEl1, "-").concat(splitEl2.toUpperCase());
}
function getUserLocalesInternal(_a) {
    var _b = _a === void 0 ? {} : _a, _c = _b.useFallbackLocale, useFallbackLocale = _c === void 0 ? true : _c, _d = _b.fallbackLocale, fallbackLocale = _d === void 0 ? 'en-US' : _d;
    var languageList = [];
    if (typeof navigator !== 'undefined') {
        var rawLanguages = navigator.languages || [];
        var languages = [];
        for (var _i = 0, rawLanguages_1 = rawLanguages; _i < rawLanguages_1.length; _i++) {
            var rawLanguagesItem = rawLanguages_1[_i];
            languages = languages.concat(fixCommas(rawLanguagesItem));
        }
        var rawLanguage = navigator.language;
        var language = rawLanguage ? fixCommas(rawLanguage) : rawLanguage;
        languageList = languageList.concat(languages, language);
    }
    if (useFallbackLocale) {
        languageList.push(fallbackLocale);
    }
    return languageList.filter(isString).map(normalizeLocale).filter(isUnique);
}
export var getUserLocales = memoize(getUserLocalesInternal, { cacheKey: JSON.stringify });
function getUserLocaleInternal(options) {
    return getUserLocales(options)[0] || null;
}
export var getUserLocale = memoize(getUserLocaleInternal, { cacheKey: JSON.stringify });
export default getUserLocale;