How to define a dynamic route in NextJs 14 API?

I want to create a blog using Next.js 14. I define this function in api/posts/[postSlug]/route.js. How can I get postSlug params in this function?

My function code:

// api/posts/[postSlug]/route.js
import prisma from "@/lib/prisma";
import { NextResponse } from "next/server";


export async function GET (request) {

    // const { postSlug } = params;
    const postSlug = 'test'
    console.log(request);

    const post = await prisma.post.findUnique({
        where: {
            slug: postSlug
        }
    })

    if (post)
        return NextResponse.json({
            post,
        })

    return NextResponse.json({
        status: 'error',
        message: 'not found!'
    })
}

You can access the dynamic route parameters of any route handler by accessing the params object within the second function argument. Here is an example:

// app/items/[slug]/route.ts

export async function GET(
  request: Request,
  { params }: { params: { slug: string } }
) {
  const { slug } = params;
  // ...
}

You can find more about route handlers and all of their abilities inside the official documentation.