diff --git a/lib/path.js b/lib/path.js
index 395fe1f35702c4..c5db4437a52408 100644
--- a/lib/path.js
+++ b/lib/path.js
@@ -55,7 +55,7 @@ function normalizeString(path, allowAboveRoot, separator, isPathSeparator) {
   let lastSlash = -1;
   let dots = 0;
   let code = 0;
-  for (var i = 0; i <= path.length; ++i) {
+  for (let i = 0; i <= path.length; ++i) {
     if (i < path.length)
       code = path.charCodeAt(i);
     else if (isPathSeparator(code))
@@ -132,7 +132,7 @@ const win32 = {
     let resolvedTail = '';
     let resolvedAbsolute = false;
 
-    for (var i = args.length - 1; i >= -1; i--) {
+    for (let i = args.length - 1; i >= -1; i--) {
       let path;
       if (i >= 0) {
         path = args[i];
@@ -370,7 +370,7 @@ const win32 = {
 
     let joined;
     let firstPart;
-    for (var i = 0; i < args.length; ++i) {
+    for (let i = 0; i < args.length; ++i) {
       const arg = args[i];
       validateString(arg, 'path');
       if (arg.length > 0) {
@@ -644,7 +644,7 @@ const win32 = {
 
     let end = -1;
     let matchedSlash = true;
-    for (var i = len - 1; i >= offset; --i) {
+    for (let i = len - 1; i >= offset; --i) {
       if (isPathSeparator(path.charCodeAt(i))) {
         if (!matchedSlash) {
           end = i;
@@ -669,10 +669,9 @@ const win32 = {
     if (ext !== undefined)
       validateString(ext, 'ext');
     validateString(path, 'path');
-    var start = 0;
-    var end = -1;
-    var matchedSlash = true;
-    var i;
+    let start = 0;
+    let end = -1;
+    let matchedSlash = true;
 
     // Check for a drive letter prefix so as not to mistake the following
     // path separator as an extra separator at the end of the path that can be
@@ -686,9 +685,9 @@ const win32 = {
     if (ext !== undefined && ext.length > 0 && ext.length <= path.length) {
       if (ext === path)
         return '';
-      var extIdx = ext.length - 1;
-      var firstNonSlashEnd = -1;
-      for (i = path.length - 1; i >= start; --i) {
+      let extIdx = ext.length - 1;
+      let firstNonSlashEnd = -1;
+      for (let i = path.length - 1; i >= start; --i) {
         const code = path.charCodeAt(i);
         if (isPathSeparator(code)) {
           // If we reached a path separator that was not part of a set of path
@@ -728,7 +727,7 @@ const win32 = {
         end = path.length;
       return path.slice(start, end);
     }
-    for (i = path.length - 1; i >= start; --i) {
+    for (let i = path.length - 1; i >= start; --i) {
       if (isPathSeparator(path.charCodeAt(i))) {
         // If we reached a path separator that was not part of a set of path
         // separators at the end of the string, stop now
@@ -751,14 +750,14 @@ const win32 = {
 
   extname(path) {
     validateString(path, 'path');
-    var start = 0;
-    var startDot = -1;
-    var startPart = 0;
-    var end = -1;
-    var matchedSlash = true;
+    let start = 0;
+    let startDot = -1;
+    let startPart = 0;
+    let end = -1;
+    let matchedSlash = true;
     // Track the state of characters (if any) we see before our first dot and
     // after any path separator we find
-    var preDotState = 0;
+    let preDotState = 0;
 
     // Check for a drive letter prefix so as not to mistake the following
     // path separator as an extra separator at the end of the path that can be
@@ -770,7 +769,7 @@ const win32 = {
       start = startPart = 2;
     }
 
-    for (var i = path.length - 1; i >= start; --i) {
+    for (let i = path.length - 1; i >= start; --i) {
       const code = path.charCodeAt(i);
       if (isPathSeparator(code)) {
         // If we reached a path separator that was not part of a set of path
@@ -823,7 +822,7 @@ const win32 = {
       return ret;
 
     const len = path.length;
-    var rootEnd = 0;
+    let rootEnd = 0;
     let code = path.charCodeAt(0);
 
     if (len === 1) {
@@ -895,15 +894,15 @@ const win32 = {
     if (rootEnd > 0)
       ret.root = path.slice(0, rootEnd);
 
-    var startDot = -1;
-    var startPart = rootEnd;
-    var end = -1;
-    var matchedSlash = true;
-    var i = path.length - 1;
+    let startDot = -1;
+    let startPart = rootEnd;
+    let end = -1;
+    let matchedSlash = true;
+    let i = path.length - 1;
 
     // Track the state of characters (if any) we see before our first dot and
     // after any path separator we find
-    var preDotState = 0;
+    let preDotState = 0;
 
     // Get non-dir info
     for (; i >= rootEnd; --i) {
@@ -975,7 +974,7 @@ const posix = {
     let resolvedPath = '';
     let resolvedAbsolute = false;
 
-    for (var i = args.length - 1; i >= -1 && !resolvedAbsolute; i--) {
+    for (let i = args.length - 1; i >= -1 && !resolvedAbsolute; i--) {
       const path = i >= 0 ? args[i] : process.cwd();
 
       validateString(path, 'path');
@@ -1035,7 +1034,7 @@ const posix = {
     if (args.length === 0)
       return '.';
     let joined;
-    for (var i = 0; i < args.length; ++i) {
+    for (let i = 0; i < args.length; ++i) {
       const arg = args[i];
       validateString(arg, 'path');
       if (arg.length > 0) {
@@ -1130,9 +1129,9 @@ const posix = {
     if (path.length === 0)
       return '.';
     const hasRoot = path.charCodeAt(0) === CHAR_FORWARD_SLASH;
-    var end = -1;
-    var matchedSlash = true;
-    for (var i = path.length - 1; i >= 1; --i) {
+    let end = -1;
+    let matchedSlash = true;
+    for (let i = path.length - 1; i >= 1; --i) {
       if (path.charCodeAt(i) === CHAR_FORWARD_SLASH) {
         if (!matchedSlash) {
           end = i;
@@ -1156,17 +1155,16 @@ const posix = {
       validateString(ext, 'ext');
     validateString(path, 'path');
 
-    var start = 0;
-    var end = -1;
-    var matchedSlash = true;
-    var i;
+    let start = 0;
+    let end = -1;
+    let matchedSlash = true;
 
     if (ext !== undefined && ext.length > 0 && ext.length <= path.length) {
       if (ext === path)
         return '';
-      var extIdx = ext.length - 1;
-      var firstNonSlashEnd = -1;
-      for (i = path.length - 1; i >= 0; --i) {
+      let extIdx = ext.length - 1;
+      let firstNonSlashEnd = -1;
+      for (let i = path.length - 1; i >= 0; --i) {
         const code = path.charCodeAt(i);
         if (code === CHAR_FORWARD_SLASH) {
           // If we reached a path separator that was not part of a set of path
@@ -1206,7 +1204,7 @@ const posix = {
         end = path.length;
       return path.slice(start, end);
     }
-    for (i = path.length - 1; i >= 0; --i) {
+    for (let i = path.length - 1; i >= 0; --i) {
       if (path.charCodeAt(i) === CHAR_FORWARD_SLASH) {
         // If we reached a path separator that was not part of a set of path
         // separators at the end of the string, stop now
@@ -1229,14 +1227,14 @@ const posix = {
 
   extname(path) {
     validateString(path, 'path');
-    var startDot = -1;
-    var startPart = 0;
-    var end = -1;
-    var matchedSlash = true;
+    let startDot = -1;
+    let startPart = 0;
+    let end = -1;
+    let matchedSlash = true;
     // Track the state of characters (if any) we see before our first dot and
     // after any path separator we find
-    var preDotState = 0;
-    for (var i = path.length - 1; i >= 0; --i) {
+    let preDotState = 0;
+    for (let i = path.length - 1; i >= 0; --i) {
       const code = path.charCodeAt(i);
       if (code === CHAR_FORWARD_SLASH) {
         // If we reached a path separator that was not part of a set of path
@@ -1288,22 +1286,22 @@ const posix = {
     if (path.length === 0)
       return ret;
     const isAbsolute = path.charCodeAt(0) === CHAR_FORWARD_SLASH;
-    var start;
+    let start;
     if (isAbsolute) {
       ret.root = '/';
       start = 1;
     } else {
       start = 0;
     }
-    var startDot = -1;
-    var startPart = 0;
-    var end = -1;
-    var matchedSlash = true;
-    var i = path.length - 1;
+    let startDot = -1;
+    let startPart = 0;
+    let end = -1;
+    let matchedSlash = true;
+    let i = path.length - 1;
 
     // Track the state of characters (if any) we see before our first dot and
     // after any path separator we find
-    var preDotState = 0;
+    let preDotState = 0;
 
     // Get non-dir info
     for (; i >= start; --i) {