remix-i18next/build/lib/language-detector.js

The easiest way to translate your Full Stack React Router apps

import { getClientLocales } from "./get-client-locales.js";
import { pick } from "./parser.js";
/**
 * The LanguageDetector contains the logic to detect the user preferred language
 * fully server-side by using a SessionStorage, Cookie, URLSearchParams, or
 * Headers.
 */
export class LanguageDetector {
    options;
    constructor(options) {
        this.options = options;
        this.isSessionOnly(options);
        this.isCookieOnly(options);
    }
    isSessionOnly(options) {
        if (options.order?.length === 1 &&
            options.order[0] === "session" &&
            !options.sessionStorage) {
            throw new Error("You need a sessionStorage if you want to only get the locale from the session");
        }
    }
    isCookieOnly(options) {
        if (options.order?.length === 1 &&
            options.order[0] === "cookie" &&
            !options.cookie) {
            throw new Error("You need a cookie if you want to only get the locale from the cookie");
        }
    }
    async detect(request) {
        let order = this.options.order ?? this.defaultOrder;
        for (let method of order) {
            let locale = null;
            if (method === "searchParams") {
                locale = this.fromSearchParams(request);
            }
            if (method === "cookie") {
                locale = await this.fromCookie(request);
            }
            if (method === "session") {
                locale = await this.fromSessionStorage(request);
            }
            if (method === "header") {
                locale = this.fromHeader(request);
            }
            if (method === "custom") {
                locale = await this.fromCustom(request);
            }
            if (locale)
                return locale;
        }
        return this.options.fallbackLanguage;
    }
    get defaultOrder() {
        let order = ["searchParams", "cookie", "session", "header"];
        if (this.options.findLocale)
            order.unshift("custom");
        return order;
    }
    fromSearchParams(request) {
        let url = new URL(request.url);
        if (!url.searchParams.has(this.options.searchParamKey ?? "lng")) {
            return null;
        }
        return this.fromSupported(url.searchParams.get(this.options.searchParamKey ?? "lng"));
    }
    async fromCookie(request) {
        if (!this.options.cookie)
            return null;
        let cookie = this.options.cookie;
        let lng = await cookie.parse(request.headers.get("Cookie"));
        if (typeof lng !== "string" || !lng)
            return null;
        return this.fromSupported(lng);
    }
    async fromSessionStorage(request) {
        if (!this.options.sessionStorage)
            return null;
        let session = await this.options.sessionStorage.getSession(request.headers.get("Cookie"));
        let lng = session.get(this.options.sessionKey ?? "lng");
        if (!lng)
            return null;
        return this.fromSupported(lng);
    }
    fromHeader(request) {
        let locales = getClientLocales(request);
        if (!locales)
            return null;
        if (Array.isArray(locales))
            return this.fromSupported(locales.join(","));
        return this.fromSupported(locales);
    }
    async fromCustom(request) {
        if (!this.options.findLocale) {
            throw new ReferenceError("You tried to find a locale using `findLocale` but it iss not defined. Change your order to not include `custom` or provide a findLocale functions.");
        }
        let locales = await this.options.findLocale(request);
        if (!locales)
            return null;
        if (Array.isArray(locales))
            return this.fromSupported(locales.join(","));
        return this.fromSupported(locales);
    }
    fromSupported(language) {
        return (pick(this.options.supportedLanguages, language ?? this.options.fallbackLanguage, { loose: false }) ||
            pick(this.options.supportedLanguages, language ?? this.options.fallbackLanguage, { loose: true }));
    }
}
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