userAgent

import { NextRequest, NextResponse, userAgent } from 'next/server'

export function middleware(request: NextRequest) {
  const url = request.nextUrl
  const { device } = userAgent(request)

  // device.type can be: 'mobile', 'tablet', 'console', 'smarttv',
  // 'wearable', 'embedded', or undefined (for desktop browsers)
  const viewport = device.type || 'desktop'

  url.searchParams.set('viewport', viewport)
  return NextResponse.rewrite(url)
}

import { NextResponse, userAgent } from 'next/server'

export function middleware(request) {
  const url = request.nextUrl
  const { device } = userAgent(request)

  // device.type can be: 'mobile', 'tablet', 'console', 'smarttv',
  // 'wearable', 'embedded', or undefined (for desktop browsers)
  const viewport = device.type || 'desktop'

  url.searchParams.set('viewport', viewport)
  return NextResponse.rewrite(url)
}