next.js/test/e2e/middleware-fetches-with-any-http-method/index.test.ts

import { nextTestSetup } from 'e2e-utils'
import { fetchViaHTTP } from 'next-test-utils'

describe('Middleware fetches with any HTTP method', () => {
  const { next } = nextTestSetup({
    files: {
      'pages/api/ping.js': `
        export default (req, res) => {
          res.send(JSON.stringify({
            method: req.method,
            headers: {...req.headers},
          }))
        }
      `,
      'middleware.js': `
        import { NextResponse } from 'next/server';

        const HTTP_ECHO_URL = 'https://next-data-api-endpoint.vercel.app/api/echo-headers';

        export default async (req) => {
          const kind = req.nextUrl.searchParams.get('kind')
          const handler = handlers[kind] ?? handlers['normal-fetch'];

          const response = await handler({url: HTTP_ECHO_URL, method: req.method});
          const json = await response.text()

          const res = NextResponse.next();
          res.headers.set('x-resolved', json ?? '{}');
          return res
        }

        const handlers = {
          'new-request': ({url, method}) =>
            fetch(new Request(url, { method, headers: { 'x-kind': 'new-request' } })),

          'normal-fetch': ({url, method}) =>
            fetch(url, { method, headers: { 'x-kind': 'normal-fetch' } })
        }
      `,
    },
    dependencies: {},
  })

  it('passes the method on a direct fetch request', async () => {
    const response = await fetchViaHTTP(
      next.url,
      '/api/ping',
      {},
      { method: 'POST' }
    )
    const json = await response.json()
    expect(json).toMatchObject({
      method: 'POST',
    })

    const headerJson = JSON.parse(response.headers.get('x-resolved'))
    expect(headerJson).toMatchObject({
      method: 'POST',
      headers: {
        'x-kind': 'normal-fetch',
      },
    })
  })

  it('passes the method when providing a Request object', async () => {
    const response = await fetchViaHTTP(
      next.url,
      '/api/ping',
      { kind: 'new-request' },
      { method: 'POST' }
    )
    const json = await response.json()
    expect(json).toMatchObject({
      method: 'POST',
    })

    const headerJson = JSON.parse(response.headers.get('x-resolved'))
    expect(headerJson).toMatchObject({
      method: 'POST',
      headers: {
        'x-kind': 'new-request',
      },
    })
  })
})