Getting Started Internationalizing (i18n) with Intlayer and Vite and Preact

import { t, type Dictionary } from "intlayer";import type { ComponentChildren } from "preact";const appContent = {  key: "app",  content: {    viteLogo: t({      en: "Vite logo",      fr: "Logo Vite",      es: "Logo Vite",    }),    preactLogo: t({      en: "Preact logo",      fr: "Logo Preact",      es: "Logo Preact",    }),    title: "Vite + Preact",    count: t({      en: "count is ",      fr: "le compte est ",      es: "el recuento es ",    }),    edit: t<ComponentChildren>({      en: (        <>          Edit <code>src/app.tsx</code> and save to test HMR        </>      ),      fr: (        <>          Éditez <code>src/app.tsx</code> et enregistrez pour tester HMR        </>      ),      es: (        <>          Edita <code>src/app.tsx</code> y guarda para probar HMR        </>      ),    }),    readTheDocs: t({      en: "Click on the Vite and Preact logos to learn more",      fr: "Cliquez sur les logos Vite et Preact pour en savoir plus",      es: "Haga clic en los logotipos de Vite y Preact para obtener más información",    }),  },} satisfies Dictionary;export default appContent;

import { useState } from "preact/hooks";import type { FunctionalComponent } from "preact";import preactLogo from "./assets/preact.svg"; // Assuming you have a preact.svgimport viteLogo from "/vite.svg";import "./app.css"; // Assuming your CSS file is named app.cssimport { IntlayerProvider, useIntlayer } from "preact-intlayer";const AppContent: FunctionalComponent = () => {  const [count, setCount] = useState(0);  const content = useIntlayer("app");  return (    <>      <div>        <a href="https://vitejs.dev" target="_blank">          <img src={viteLogo} class="logo" alt={content.viteLogo.value} />        </a>        <a href="https://preactjs.com" target="_blank">          <img            src={preactLogo}            class="logo preact"            alt={content.preactLogo.value}          />        </a>      </div>      <h1>{content.title}</h1>      <div class="card">        <button onClick={() => setCount((count) => count + 1)}>          {content.count}          {count}        </button>        <p>{content.edit}</p>      </div>      <p class="read-the-docs">{content.readTheDocs}</p>    </>  );};const App: FunctionalComponent = () => (  <IntlayerProvider>    <AppContent />  </IntlayerProvider>);export default App;

import type { FunctionalComponent } from "preact";import { Locales } from "intlayer";import { useLocale } from "preact-intlayer";const LocaleSwitcher: FunctionalComponent = () => {  const { setLocale } = useLocale();  return (    <button onClick={() => setLocale(Locales.ENGLISH)}>      Change Language to English    </button>  );};export default LocaleSwitcher;

import { type Locales, configuration, getPathWithoutLocale } from "intlayer";import { ComponentChildren, FunctionalComponent } from "preact";import { IntlayerProvider } from "preact-intlayer";import { LocationProvider, useLocation } from "preact-iso";import { useEffect } from "preact/hooks";const { internationalization, middleware } = configuration;const { locales, defaultLocale } = internationalization;const Navigate: FunctionalComponent<{ to: string; replace?: boolean }> = ({  to,  replace,}) => {  const { route } = useLocation();  useEffect(() => {    route(to, replace);  }, [to, replace, route]);  return null;};/** * A component that handles localization and wraps children with the appropriate locale context. * It manages URL-based locale detection and validation. */const AppLocalized: FunctionalComponent<{  children: ComponentChildren;  locale?: Locales;}> = ({ children, locale }) => {  const { path: pathname, url } = useLocation();  if (!url) {    return null;  }  const search = url.substring(pathname.length);  // Determine the current locale, falling back to the default if not provided  const currentLocale = locale ?? defaultLocale;  // Remove the locale prefix from the path to construct a base path  const pathWithoutLocale = getPathWithoutLocale(    pathname // Current URL path  );  /**   * If middleware.prefixDefault is true, the default locale should always be prefixed.   */  if (middleware.prefixDefault) {    // Validate the locale    if (!locale || !locales.includes(locale)) {      // Redirect to the default locale with the updated path      return (        <Navigate          to={`/${defaultLocale}/${pathWithoutLocale}${search}`}          replace // Replace the current history entry with the new one        />      );    }    // Wrap children with the IntlayerProvider and set the current locale    return (      <IntlayerProvider locale={currentLocale}>{children}</IntlayerProvider>    );  } else {    /**     * When middleware.prefixDefault is false, the default locale is not prefixed.     * Ensure that the current locale is valid and not the default locale.     */    if (      currentLocale.toString() !== defaultLocale.toString() &&      !locales        .filter(          (loc) => loc.toString() !== defaultLocale.toString() // Exclude the default locale        )        .includes(currentLocale) // Check if the current locale is in the list of valid locales    ) {      // Redirect to the path without locale prefix      return <Navigate to={`${pathWithoutLocale}${search}`} replace />;    }    // Wrap children with the IntlayerProvider and set the current locale    return (      <IntlayerProvider locale={currentLocale}>{children}</IntlayerProvider>    );  }};const RouterContent: FunctionalComponent<{  children: ComponentChildren;}> = ({ children }) => {  const { path } = useLocation();  if (!path) {    return null;  }  const pathLocale = path.split("/")[1] as Locales;  const isLocaleRoute = locales    .filter((locale) => middleware.prefixDefault || locale !== defaultLocale)    .some((locale) => locale.toString() === pathLocale);  if (isLocaleRoute) {    return <AppLocalized locale={pathLocale}>{children}</AppLocalized>;  }  return (    <AppLocalized      locale={!middleware.prefixDefault ? defaultLocale : undefined}    >      {children}    </AppLocalized>  );};/** * A router component that sets up locale-specific routes. * It uses preact-iso to manage navigation and render localized components. */export const LocaleRouter: FunctionalComponent<{  children: ComponentChildren;}> = ({ children }) => (  <LocationProvider>    <RouterContent>{children}</RouterContent>  </LocationProvider>);

import { LocaleRouter } from "./components/LocaleRouter";import type { FunctionalComponent } from "preact";// ... Your AppContent component (defined in Step 5)const App: FunctionalComponent = () => (  <LocaleRouter>    <AppContent />  </LocaleRouter>);export default App;

import { useLocation, route } from "preact-iso";import {  Locales,  getHTMLTextDir,  getLocaleName,  getLocalizedUrl,} from "intlayer";import { useLocale } from "preact-intlayer";import type { FunctionalComponent } from "preact";const LocaleSwitcher: FunctionalComponent = () => {  const location = useLocation();  const { locale, availableLocales, setLocale } = useLocale({    onLocaleChange: (newLocale) => {      const currentFullPath = location.url; // preact-iso provides the full url      // Construct the URL with the updated locale      // Example: /es/about?foo=bar      const pathWithLocale = getLocalizedUrl(currentFullPath, newLocale);      // Update the URL path      route(pathWithLocale, true); // true for replace    },  });  return (    <div>      <button popovertarget="localePopover">{getLocaleName(locale)}</button>      <div id="localePopover" popover="auto">        {availableLocales.map((localeItem) => (          <a            href={getLocalizedUrl(location.url, localeItem)}            hreflang={localeItem}            aria-current={locale === localeItem ? "page" : undefined}            onClick={(e) => {              e.preventDefault();              setLocale(localeItem);              // Programmatic navigation after setting locale will be handled by onLocaleChange            }}            key={localeItem}          >            <span>              {/* Locale - e.g. FR */}              {localeItem}            </span>            <span>              {/* Language in its own Locale - e.g. Français */}              {getLocaleName(localeItem, localeItem)}            </span>            <span dir={getHTMLTextDir(localeItem)} lang={localeItem}>              {/* Language in current Locale - e.g. Francés with current locale set to Locales.SPANISH */}              {getLocaleName(localeItem, locale)}            </span>            <span dir="ltr" lang={Locales.ENGLISH}>              {/* Language in English - e.g. French */}              {getLocaleName(localeItem, Locales.ENGLISH)}            </span>          </a>        ))}      </div>    </div>  );};export default LocaleSwitcher;

import { useEffect } from "preact/hooks";import { useLocale } from "preact-intlayer";import { getHTMLTextDir } from "intlayer";/** * Updates the HTML <html> element's `lang` and `dir` attributes based on the current locale. * - `lang`: Informs browsers and search engines of the page's language. * - `dir`: Ensures the correct reading order (e.g., 'ltr' for English, 'rtl' for Arabic). * * This dynamic update is essential for proper text rendering, accessibility, and SEO. */export const useI18nHTMLAttributes = () => {  const { locale } = useLocale();  useEffect(() => {    // Update the language attribute to the current locale.    document.documentElement.lang = locale;    // Set the text direction based on the current locale.    document.documentElement.dir = getHTMLTextDir(locale);  }, [locale]);};

import type { FunctionalComponent } from "preact";import { IntlayerProvider } from "preact-intlayer"; // useIntlayer already imported if AppContent needs itimport { useI18nHTMLAttributes } from "./hooks/useI18nHTMLAttributes";import "./app.css";// AppContent definition from Step 5const AppWithHooks: FunctionalComponent = () => {  // Apply the hook to update the <html> tag's lang and dir attributes based on the locale.  useI18nHTMLAttributes();  // Assuming AppContent is your main content display component from Step 5  return <AppContent />;};const App: FunctionalComponent = () => (  <IntlayerProvider>    <AppWithHooks />  </IntlayerProvider>);export default App;

import { getLocalizedUrl } from "intlayer";import { useLocale, useLocation, route } from "preact-intlayer"; // Assuming useLocation and route can be from preact-iso via preact-intlayer if re-exported, or import directly// If not re-exported, import directly: import { useLocation, route } from "preact-iso";import type { JSX } from "preact"; // For HTMLAttributesimport { forwardRef } from "preact/compat"; // For forwarding refsexport interface LocalizedLinkProps  extends JSX.HTMLAttributes<HTMLAnchorElement> {  href: string;  replace?: boolean; // Optional: to replace history state}/** * Utility function to check whether a given URL is external. * If the URL starts with http:// or https://, it's considered external. */export const checkIsExternalLink = (href?: string): boolean =>  /^https?:\/\//.test(href ?? "");/** * A custom Link component that adapts the href attribute based on the current locale. * For internal links, it uses `getLocalizedUrl` to prefix the URL with the locale (e.g., /fr/about). * This ensures that navigation stays within the same locale context. * It uses a standard <a> tag but can trigger client-side navigation using preact-iso's `route`. */export const LocalizedLink = forwardRef<HTMLAnchorElement, LocalizedLinkProps>(  ({ href, children, onClick, replace = false, ...props }, ref) => {    const { locale } = useLocale();    const location = useLocation(); // from preact-iso    const isExternalLink = checkIsExternalLink(href);    const hrefI18n =      href && !isExternalLink ? getLocalizedUrl(href, locale) : href;    const handleClick = (event: JSX.TargetedMouseEvent<HTMLAnchorElement>) => {      if (onClick) {        onClick(event);      }      if (        !isExternalLink &&        href && // Ensure href is defined        event.button === 0 && // Left click        !event.metaKey &&        !event.ctrlKey &&        !event.shiftKey &&        !event.altKey && // Standard modifiers check        !props.target // Not targeting a new tab/window      ) {        event.preventDefault();        if (location.url !== hrefI18n) {          // Only navigate if the URL is different          route(hrefI18n, replace); // Use preact-iso's route        }      }    };    return (      <a href={hrefI18n} ref={ref} onClick={handleClick} {...props}>        {children}      </a>    );  });