dns: simplify dns.promises warning logic

cjihrig · BridgeAR · commit 2dfaa480dec5 · 2018-12-05T20:07:15.000+01:00
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: #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>
diff --git a/lib/dns.js b/lib/dns.js
@@ -50,8 +50,7 @@ const {
 
 const dnsException = errors.dnsException;
 
-let promisesWarn = true;
-let promises; // Lazy loaded
+let promises = null; // Lazy loaded
 
 function onlookup(err, addresses) {
 if (err) {
@@ -269,7 +268,7 @@ function defaultResolverSetServers(servers) {
 setDefaultResolver(resolver);
 bindDefaultResolver(module.exports, Resolver.prototype);
 
- if (promises !== undefined)
+ if (promises !== null)
 bindDefaultResolver(promises, promises.Resolver.prototype);
 }
 
@@ -318,10 +317,9 @@ 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');
 }

-Original file line number
+Diff line change
 constdnsException=errors.dnsException;
 -letpromisesWarn=true;
 -letpromises;// Lazy loaded
 +letpromises=null;// Lazy loaded
 functiononlookup(err,addresses){
 if(err){
 setDefaultResolver(resolver);
 bindDefaultResolver(module.exports,Resolver.prototype);
 -if(promises!==undefined)
 +if(promises!==null)
 bindDefaultResolver(promises,promises.Resolver.prototype);
+}
 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');
+}