@flotiq/nextjs-internationalization

Lightweight internationalization helpers for Next.js applications.

This package provides:

• A middleware that redirects requests to language-prefixed paths (for example /en/...) based on the Accept-Language header.
• A helper function _translate that applies translations from an object's __translations array onto the object recursively.

Installation

Install the package in your Next.js project:

npm install @flotiq/nextjs-internationalization

Requirements

• Next.js: 15.0.0 or higher
• @formatjs/intl-localematcher: 0.6.2 or higher
• negotiator: 1.0.0 or higher

Middleware: automatic language redirect

Use createInternationalizationMiddleware in your Next.js middleware to automatically redirect users to a path prefixed with the chosen locale.

Create a middleware.ts file and use internationalization helper:

import { createInternationalizationMiddleware } from "@flotiq/nextjs-internationalization";

export async function middleware(request: Request) {
	const locales = ["en", "pl"];
	const defaultLocale = "en";
    return createInternationalizationMiddleware(request, locales, 'pl');
}

How it behaves:

• If the request path already starts with one of the provided locales (for example /pl), no redirect is performed.
• Otherwise it picks the best matching locale from the Accept-Language header using negotiator and @formatjs/intl-localematcher, then returns a redirect to the same path prefixed with the chosen locale.

Helper: _translate

_translate applies translations embedded in an object. The object can include a __translations array containing translation objects with a __language property. The helper will merge matching translation properties into the base object recursively.

Example:

import { _translate } from "@flotiq/nextjs-internationalization";

const item = {
	title: "Hello",
	content: "Default content",
	__translations: [
		{ __language: "pl", title: "Cześć", content: "Treść po polsku" }
	]
};

const translated = _translate(item, "pl");
// translated.title === 'Cześć'

The helper walks nested objects and arrays recursively and applies translations where available.