feat(api): typescript

api/services/dns.ts

@@ -0,0 +1,30 @@
+import dns from 'dns'
+import { send, sendError, NowRequest, NowResponse } from '../util/http'
+
+function resolvePromise(hostname: string): Promise<string[]> {
+  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) {
+  const { query } = req.query
+
+  if (!query) {
+    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 res.status(200).json({ availability: true })
+    }
+    sendError(res, err)
+  }
+}