tools: enable block-scoped-var eslint rule

PR-URL: https://github.com/nodejs/node/pull/27616
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>

5 files changed, 19 insertions, 12 deletions

diff --git a/lib/dgram.js b/lib/dgram.js
index b38aa39c21..cb20c4499a 100644
--- a/lib/dgram.js
+++ b/lib/dgram.js
@@ -91,8 +91,9 @@ function Socket(type, listener) {
   let recvBufferSize;
   let sendBufferSize;
 
+  let options;
   if (type !== null && typeof type === 'object') {
-    var options = type;
+    options = type;
     type = options.type;
     lookup = options.lookup;
     recvBufferSize = options.recvBufferSize;
diff --git a/lib/internal/child_process.js b/lib/internal/child_process.js
index 03c0ed9159..2f081d9111 100644
--- a/lib/internal/child_process.js
+++ b/lib/internal/child_process.js
@@ -693,6 +693,8 @@ function setupChannel(target, channel) {
       options = { swallowErrors: options };
     }
 
+    let obj;
+
     // Package messages with a handle object
     if (handle) {
       // This message will be handled by an internalMessage event handler
@@ -727,7 +729,7 @@ function setupChannel(target, channel) {
         return this._handleQueue.length === 1;
       }
 
-      var obj = handleConversion[message.type];
+      obj = handleConversion[message.type];
 
       // convert TCP object to native handle object
       handle = handleConversion[message.type].send.call(target,
diff --git a/lib/internal/util.js b/lib/internal/util.js
index 14c8baa68c..ed2493d9b4 100644
--- a/lib/internal/util.js
+++ b/lib/internal/util.js
@@ -316,12 +316,13 @@ promisify.custom = kCustomPromisifiedSymbol;
 function join(output, separator) {
   let str = '';
   if (output.length !== 0) {
-    for (var i = 0; i < output.length - 1; i++) {
+    const lastIndex = output.length - 1;
+    for (let i = 0; i < lastIndex; i++) {
       // It is faster not to use a template string here
       str += output[i];
       str += separator;
     }
-    str += output[i];
+    str += output[lastIndex];
   }
   return str;
 }
diff --git a/lib/internal/util/inspect.js b/lib/internal/util/inspect.js
index 21b9921dbe..1e7277ef38 100644
--- a/lib/internal/util/inspect.js
+++ b/lib/internal/util/inspect.js
@@ -312,7 +312,8 @@ function strEscape(str) {
 
   let result = '';
   let last = 0;
-  for (var i = 0; i < str.length; i++) {
+  const lastIndex = str.length;
+  for (let i = 0; i < lastIndex; i++) {
     const point = str.charCodeAt(i);
     if (point === singleQuote || point === 92 || point < 32) {
       if (last === i) {
@@ -324,7 +325,7 @@ function strEscape(str) {
     }
   }
 
-  if (last !== i) {
+  if (last !== lastIndex) {
     result += str.slice(last);
   }
   return addQuotes(result, singleQuote);
@@ -1061,10 +1062,11 @@ function formatPrimitive(fn, value, ctx) {
       if (matches.length > 1) {
         const indent = ' '.repeat(ctx.indentationLvl);
         let res = `${fn(strEscape(matches[0]), 'string')} +\n`;
-        for (var i = 1; i < matches.length - 1; i++) {
+        const lastIndex = matches.length - 1;
+        for (let i = 1; i < lastIndex; i++) {
           res += `${indent}  ${fn(strEscape(matches[i]), 'string')} +\n`;
         }
-        res += `${indent}  ${fn(strEscape(matches[i]), 'string')}`;
+        res += `${indent}  ${fn(strEscape(matches[lastIndex]), 'string')}`;
         return res;
       }
     }
@@ -1187,10 +1189,10 @@ function formatTypedArray(ctx, value, recurseTimes) {
   const elementFormatter = value.length > 0 && typeof value[0] === 'number' ?
     formatNumber :
     formatBigInt;
-  for (var i = 0; i < maxLength; ++i)
+  for (let i = 0; i < maxLength; ++i)
     output[i] = elementFormatter(ctx.stylize, value[i]);
   if (remaining > 0) {
-    output[i] = `... ${remaining} more item${remaining > 1 ? 's' : ''}`;
+    output[maxLength] = `... ${remaining} more item${remaining > 1 ? 's' : ''}`;
   }
   if (ctx.showHidden) {
     // .buffer goes last, it's not a primitive like the others.
diff --git a/lib/url.js b/lib/url.js
index be483ae2bc..665bd43614 100644
--- a/lib/url.js
+++ b/lib/url.js
@@ -267,9 +267,10 @@ Url.prototype.parse = function parse(url, parseQueryString, slashesDenoteHost) {
   // user@server is *always* interpreted as a hostname, and url
   // resolution will treat //foo/bar as host=foo,path=bar because that's
   // how the browser resolves relative URLs.
+  let slashes;
   if (slashesDenoteHost || proto || hostPattern.test(rest)) {
-    var slashes = rest.charCodeAt(0) === CHAR_FORWARD_SLASH &&
-                  rest.charCodeAt(1) === CHAR_FORWARD_SLASH;
+    slashes = rest.charCodeAt(0) === CHAR_FORWARD_SLASH &&
+              rest.charCodeAt(1) === CHAR_FORWARD_SLASH;
     if (slashes && !(proto && hostlessProtocol.has(lowerProto))) {
       rest = rest.slice(2);
       this.slashes = true;