namae/api/services/existence/[query].ts

import isURL from 'validator/lib/isURL'
import { send, sendError, fetch } from '../../../util/http'
import { NowRequest, NowResponse } from '@vercel/node'

export default async function handler(
  req: NowRequest,
  res: NowResponse
): Promise<void> {
  const { query } = req.query

  if (!query || typeof query !== 'string') {
    return sendError(res, new Error('no query given'))
  }

  if (!isURL(query)) {
    return sendError(res, new Error('Invalid URL: ' + query))
  }

  try {
    const response = await fetch(`https://${query}`)
    const availability = response.status === 404
    send(res, { availability })
  } catch (err) {
    console.log(err.code)
    if (err.code === 'ENOTFOUND') {
      return send(res, { availability: true })
    }
    sendError(res, err)
  }
}