process: replace var with let/const

PR-URL: #30382
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: David Carlier <devnexen@gmail.com>
Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>
Reviewed-By: Beth Griggs <Bethany.Griggs@uk.ibm.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>

Author: deadbeef84

lib/internal/process/stdio.js

@@ -19,9 +19,9 @@ function dummyDestroy(err, cb) {
 }
 
 functiongetMainThreadStdio(){
-varstdin;
-varstdout;
-varstderr;
+letstdin;
+letstdout;
+letstderr;
 
 functiongetStdout(){
 if(stdout)returnstdout;
@@ -53,7 +53,7 @@ function getMainThreadStdio() {
 
 switch(guessHandleType(fd)){
 case'TTY':
-vartty=require('tty');
+consttty=require('tty');
 stdin=newtty.ReadStream(fd,{
 highWaterMark: 0,
 readable: true,
@@ -62,13 +62,13 @@ function getMainThreadStdio() {
 break;
 
 case'FILE':
-varfs=require('fs');
+constfs=require('fs');
 stdin=newfs.ReadStream(null,{fd: fd,autoClose: false});
 break;
 
 case'PIPE':
 case'TCP':
-varnet=require('net');
+constnet=require('net');
 
 // It could be that process has been started with an IPC channel
 // sitting on fd=0, in such case the pipe for this fd is already
@@ -147,11 +147,11 @@ function getMainThreadStdio() {
 }
 
 functioncreateWritableStdioStream(fd){
-varstream;
+letstream;
 // Note stream._type is used for test-module-load-list.js
 switch(guessHandleType(fd)){
 case'TTY':
-vartty=require('tty');
+consttty=require('tty');
 stream=newtty.WriteStream(fd);
 stream._type='tty';
 break;
@@ -164,7 +164,7 @@ function createWritableStdioStream(fd) {
 
 case'PIPE':
 case'TCP':
-varnet=require('net');
+constnet=require('net');
 
 // If fd is already being used for the IPC channel, libuv will return
 // an error when trying to use it again. In that case, create the socket