cluster: use Map to track callbacks

Use a Map to avoid delete operations in callback tracking. PR-URL: #23125 Reviewed-By: Gus Caplan <[email protected]> Reviewed-By: Michaël Zasso <[email protected]> Reviewed-By: Anna Henningsen <[email protected]> Reviewed-By: James M Snell <[email protected]> Reviewed-By: Trivikram Kamat <[email protected]> Reviewed-By: Denys Otrishko <[email protected]>

Author: cjihrig

lib/internal/cluster/utils.js

@@ -7,7 +7,7 @@ module.exports ={
 handles: {}// Used in tests.
 };
 
-constcallbacks={};
+constcallbacks=newMap();
 varseq=0;
 
 functionsendHelper(proc,message,handle,cb){
@@ -18,7 +18,7 @@ function sendHelper(proc, message, handle, cb){
 message=util._extend({cmd: 'NODE_CLUSTER'},message);
 
 if(typeofcb==='function')
-callbacks[seq]=cb;
+callbacks.set(seq,cb);
 
 message.seq=seq;
 seq+=1;
@@ -34,9 +34,13 @@ function internal(worker, cb){
 
 varfn=cb;
 
-if(message.ack!==undefined&&callbacks[message.ack]!==undefined){
-fn=callbacks[message.ack];
-deletecallbacks[message.ack];
+if(message.ack!==undefined){
+constcallback=callbacks.get(message.ack);
+
+if(callback!==undefined){
+fn=callback;
+callbacks.delete(message.ack);
+}
 }
 
 fn.apply(worker,arguments);