How to retrieve the locale from the cookies / headers

    Using Hooks (Recommended)

    For most use cases, it is recommended to retrieve the current locale using the useLocale hook because it is auto-resolved. This works similarly to the useLocale composable in Vue.js.

    ts
    import { useLocale } from "next-intlayer";// or import { useLocale } from "react-intlayer";// or import { useLocale } from "vue-intlayer";ts;// Client-side usageconst { locale } = useLocale();

    For server components, you can import it from:

    tsx
    import { useLocale } from "next-intlayer/server";const Test = () => {  const { locale } = useLocale();  return <>{locale}</>;};const Page = async ({ params }) => {  const { locale } = await params;  return (    <IntlayerServerProvider locale={locale}>      <Test />    </IntlayerServerProvider>  );};

    There is also a useLocaleCookie hook that only resolves the cookie value.

    Manual Cookie Configuration

    You can declare a custom cookie name as

    ts
    import { type IntlayerConfig } from "intlayer";const config: IntlayerConfig = {  middleware: {    cookieName: "myCustomLocaleCookie", // default is 'intlayer-locale'  },};export default config;

    the retrieve it as

    Client-side

    ts
    // Using the default cookie nameconst locale = document.cookie  .split("; ")  .find((row) => row.startsWith("intlayer-locale="))  ?.split("=")[1];// Using custom cookie nameconst locale = document.cookie  .split("; ")  .find((row) => row.startsWith("myCustomLocaleCookie="))  ?.split("=")[1];

    Server-side (Next.js)

    ts
    import { cookies } from "next/headers";// Using the default cookie nameconst locale = cookies().get("intlayer-locale")?.value;// Using custom cookie nameconst locale = cookies().get("myCustomLocaleCookie")?.value;

    If locale not set yet

    The locale is set as a cookie only once the user explicitly selects the locale. By default, for new visitors, the locale is interpreted from the header fields.

    You can detect the user's preferred locale from the request headers. Here's an example of how to handle this:

    ts
    /** * Detects the locale from the request headers * * The accept-language header is the most important one for locale detection. * It contains a list of language codes with quality values (q-values) that indicate * the user's preferred languages in order of preference. * * Example: "en-US,en;q=0.9,fr;q=0.8,es;q=0.7" * - en-US is the primary language (q=1.0 is implied) * - en is the second choice (q=0.9) * - fr is the third choice (q=0.8) * - es is the fourth choice (q=0.7) */import { localeDetector } from "@intlayer/core";/** * Example of negotiator headers that browsers typically send * These headers help determine the user's preferred language */const exampleNegotiatorHeaders: Record<string, string> = {  "accept-language": "en-US,en;q=0.9,fr;q=0.8,es;q=0.7",  "accept":    "text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8",  "user-agent":    "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.4472.124 Safari/537.36",};// Usage example:const detectedLocale = localeDetector(exampleNegotiatorHeaders);