child_process: replace var with let/const

PR-URL: #30389
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: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>

lib/child_process.js

@@ -55,10 +55,10 @@ function fork(modulePath /* , args, options */) {
   validateString(modulePath, 'modulePath');
 
   // Get options and args arguments.
-  var execArgv;
-  var options = {};
-  var args = [];
-  var pos = 1;
+  let execArgv;
+  let options = {};
+  let args = [];
+  let pos = 1;
   if (pos < arguments.length && Array.isArray(arguments[pos])) {
     args = arguments[pos++];
   }
@@ -231,23 +231,23 @@ function execFile(file /* , args, options, callback */) {
     windowsVerbatimArguments: !!options.windowsVerbatimArguments
   });
 
-  var encoding;
+  let encoding;
   const _stdout = [];
   const _stderr = [];
   if (options.encoding !== 'buffer' && Buffer.isEncoding(options.encoding)) {
     encoding = options.encoding;
   } else {
     encoding = null;
   }
-  var stdoutLen = 0;
-  var stderrLen = 0;
-  var killed = false;
-  var exited = false;
-  var timeoutId;
+  let stdoutLen = 0;
+  let stderrLen = 0;
+  let killed = false;
+  let exited = false;
+  let timeoutId;
 
-  var ex = null;
+  let ex = null;
 
-  var cmd = file;
+  let cmd = file;
 
   function exithandler(code, signal) {
     if (exited) return;
@@ -261,8 +261,8 @@ function execFile(file /* , args, options, callback */) {
     if (!callback) return;
 
     // merge chunks
-    var stdout;
-    var stderr;
+    let stdout;
+    let stderr;
     if (encoding ||
       (
         child.stdout &&
@@ -580,15 +580,15 @@ function spawnSync(file, args, options) {
   options.stdio = getValidStdio(options.stdio || 'pipe', true).stdio;
 
   if (options.input) {
-    var stdin = options.stdio[0] = { ...options.stdio[0] };
+    const stdin = options.stdio[0] = { ...options.stdio[0] };
     stdin.input = options.input;
   }
 
   // We may want to pass data in on any given fd, ensure it is a valid buffer
-  for (var i = 0; i < options.stdio.length; i++) {
-    var input = options.stdio[i] && options.stdio[i].input;
+  for (let i = 0; i < options.stdio.length; i++) {
+    const input = options.stdio[i] && options.stdio[i].input;
     if (input != null) {
-      var pipe = options.stdio[i] = { ...options.stdio[i] };
+      const pipe = options.stdio[i] = { ...options.stdio[i] };
       if (isArrayBufferView(input)) {
         pipe.input = input;
       } else if (typeof input === 'string') {
@@ -609,11 +609,11 @@ function spawnSync(file, args, options) {
 
 
 function checkExecSyncError(ret, args, cmd) {
-  var err;
+  let err;
   if (ret.error) {
     err = ret.error;
   } else if (ret.status !== 0) {
-    var msg = 'Command failed: ';
+    let msg = 'Command failed: ';
     msg += cmd || args.join(' ');
     if (ret.stderr && ret.stderr.length > 0)
       msg += `\n${ret.stderr.toString()}`;