With the App Router in Next.js, we use a different approach to define routes and handle query parameters. Here’s how to handle query parameters with the App Router in Next.js:

1. Client-Side Query Parameters

With the App Router, you can still use the useRouter hook from next/router to access query parameters on the client-side.

// app/client/page.js
"use client";

import { useRouter } from 'next/router';

const ClientPage = () => {
    const router = useRouter();
    const { param1, param2 } = router.query; // Access query parameters

    return (
        <div>
            <h1>Client-Side Query Params</h1>
            <p>Param1: {param1}</p>
            <p>Param2: {param2}</p>
        </div>
    );
};

export default ClientPage;

2. Server-Side Query Parameters

For server-side rendering (SSR) or static generation in the App Router, you can access query parameters in the layout or page components using headers or searchParams.

Example with Server Component:

// app/server/page.js

export default async function ServerPage({ searchParams }) {
    const { param1, param2 } = searchParams;

    return (
        <div>
            <h1>Server-Side Query Params</h1>
            <p>Param1: {param1}</p>
            <p>Param2: {param2}</p>
        </div>
    );
}

3. API Routes

For the full string use the url and/or pull the request parameters from that url using .get.

import { NextRequest } from 'next/server'

export async function GET(req: NextRequest) {
    const reqUrl = req.url
    const { searchParams } = new URL(reqUrl)
    console.log(searchParams.get("param1")) // should print lorem
}

Usage

To see the different contexts in action, you can navigate to the following URLs:

• Client-Side: http://localhost:3000/client?param1=value1&param2=value2

• Server-Side: http://localhost:3000/server?param1=value1&param2=value2

• API Route: http://localhost:3000/api/query?param1=value1&param2=value2

This setup allows you to parse and use query parameters in a Next.js application using the App Router on the client-side, server-side, and in API routes.