From 8af4f4413030f6b3b75d1c567857aa873fb97fda Mon Sep 17 00:00:00 2001
From: cjihrig <cjihrig@gmail.com>
Date: Sun, 2 Dec 2018 12:25:39 -0500
Subject: [PATCH] dns: simplify dns.promises warning logic

dns.promises is lazy loaded. Instead of using a seaparate
Boolean flag to track whether or not it has been loaded, just
inspect the state of the lazy loaded module itself.

PR-URL: https://github.com/nodejs/node/pull/24788
Reviewed-By: Anto Aravinth <anto.aravinth.cse@gmail.com>
Reviewed-By: Weijia Wang <starkwang@126.com>
Reviewed-By: Masashi Hirano <shisama07@gmail.com>
Reviewed-By: Jeremiah Senkpiel <fishrock123@rocketmail.com>
---
 lib/dns.js | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/lib/dns.js b/lib/dns.js
index b2ae92a9d6999c..f90d7c1a57b541 100644
--- a/lib/dns.js
+++ b/lib/dns.js
@@ -49,8 +49,7 @@ const {
 
 const dnsException = errors.dnsException;
 
-let promisesWarn = true;
-let promises; // Lazy loaded
+let promises = null; // Lazy loaded
 
 function onlookup(err, addresses) {
   if (err) {
@@ -267,7 +266,7 @@ function defaultResolverSetServers(servers) {
   setDefaultResolver(resolver);
   bindDefaultResolver(module.exports, Resolver.prototype);
 
-  if (promises !== undefined)
+  if (promises !== null)
     bindDefaultResolver(promises, promises.Resolver.prototype);
 }
 
@@ -316,10 +315,9 @@ Object.defineProperties(module.exports, {
     configurable: true,
     enumerable: false,
     get() {
-      if (promisesWarn) {
+      if (promises === null) {
         promises = require('internal/dns/promises');
         promises.setServers = defaultResolverSetServers;
-        promisesWarn = false;
         process.emitWarning('The dns.promises API is experimental',
                             'ExperimentalWarning');
       }