import dns from 'dns' import { send, sendError } from '../../../util/http' import { NowRequest, NowResponse } from '@vercel/node' function resolvePromise(hostname: string): Promise { return new Promise((resolve, reject) => { dns.resolve4(hostname, function (err, addresses) { if (err) return reject(err) resolve(addresses) }) }) } export default async function handler( req: NowRequest, res: NowResponse ): Promise { const { query } = req.query if (!query || typeof query !== 'string') { return sendError(res, new Error('No query given')) } try { const response = await resolvePromise(query) const availability = response && response.length > 0 ? false : true send(res, { availability }) } catch (err) { if (err.code === 'ENODATA' || err.code === 'ENOTFOUND') { return send(res, { availability: true }) } sendError(res, err) } }