Next.js: Edge runtime — пример кода

// app/api/geo/route.ts — a perfect Edge use case: pure I/O + geo-awareness
export const runtime = 'edge';

export async function GET(req: Request) {
  // Geo headers are injected by the edge network — free, no lookup
  const country = req.headers.get('x-vercel-ip-country') ?? 'US';

  // ✅ Web fetch to an HTTP data source — no TCP pool, no Node driver
  const res = await fetch(` {
    next: { revalidate: 60 }, // cached at the edge for 60s
  });

  return Response.json(await res.json());
}

// ❌ This will NOT build on the Edge runtime
export const runtime = 'edge';
import fs from 'node:fs';           // no filesystem in an isolate
import { Client } from 'pg';        // raw TCP driver — connection storm
export async function GET() {
  const tpl = fs.readFileSync('./email.html'); // throws
  // ...
}