http: lazy allocate cookies array

PR-URL: #59734 Reviewed-By: Juan José Arboleda <[email protected]> Reviewed-By: Ethan Arrowood <[email protected]> Reviewed-By: Tim Perry <[email protected]> Reviewed-By: Marco Ippolito <[email protected]> Reviewed-By: Jake Yuesong Li <[email protected]> Reviewed-By: Matteo Collina <[email protected]> Reviewed-By: Ruben Bridgewater <[email protected]> Reviewed-By: Luigi Pinca <[email protected]>

Author: ronag

lib/_http_outgoing.js

@@ -673,20 +673,22 @@ OutgoingMessage.prototype.setHeaders = function setHeaders(headers){
 // We also cannot safely split by comma.
 // To avoid setHeader overwriting the previous value we push
 // set-cookie values in array and set them all at once.
-constcookies=[];
+letcookies=null;
 
 for(const{0: key,1: value}ofheaders){
 if(key==='set-cookie'){
 if(ArrayIsArray(value)){
+cookies??=[];
 cookies.push(...value);
 }else{
+cookies??=[];
 cookies.push(value);
 }
 continue;
 }
 this.setHeader(key,value);
 }
-if(cookies.length){
+if(cookies!=null){
 this.setHeader('set-cookie',cookies);
 }