lib: replace var with let/const

PR-URL: #30404
Reviewed-By: James M Snell <[email protected]>
Reviewed-By: Gireesh Punathil <[email protected]>
Reviewed-By: Ruben Bridgewater <[email protected]>
Reviewed-By: Trivikram Kamat <[email protected]>

Author: Tembrechts

lib/timers.js

@@ -118,7 +118,7 @@ function setTimeout(callback, after, arg1, arg2, arg3) {
     throw new ERR_INVALID_CALLBACK(callback);
   }
 
-  var i, args;
+  let i, args;
   switch (arguments.length) {
     // fast cases
     case 1:
@@ -164,7 +164,7 @@ function setInterval(callback, repeat, arg1, arg2, arg3) {
     throw new ERR_INVALID_CALLBACK(callback);
   }
 
-  var i, args;
+  let i, args;
   switch (arguments.length) {
     // fast cases
     case 1:
@@ -248,7 +248,7 @@ function setImmediate(callback, arg1, arg2, arg3) {
     throw new ERR_INVALID_CALLBACK(callback);
   }
 
-  var i, args;
+  let i, args;
   switch (arguments.length) {
     // fast cases
     case 1: