path: remove StringPrototypeCharCodeAt from lib/path

Remove `StringPrototypeCharCodeAt` from `posix.resolve`,
`posix.normalize`, `posix.parse`

Author: HBSPS

lib/path.js

@@ -1173,8 +1173,7 @@ const posix = {
       }
 
       resolvedPath = `${path}/${resolvedPath}`;
-      resolvedAbsolute =
-        StringPrototypeCharCodeAt(path, 0) === CHAR_FORWARD_SLASH;
+      resolvedAbsolute = path[0] === '/';
     }
 
     // At this point the path should be resolved to a full absolute path, but
@@ -1200,10 +1199,8 @@ const posix = {
     if (path.length === 0)
       return '.';
 
-    const isAbsolute =
-      StringPrototypeCharCodeAt(path, 0) === CHAR_FORWARD_SLASH;
-    const trailingSeparator =
-      StringPrototypeCharCodeAt(path, path.length - 1) === CHAR_FORWARD_SLASH;
+    const isAbsolute = path[0] === '/';
+    const trailingSeparator = path[path.length - 1] === '/';
 
     // Normalize the path
     path = normalizeString(path, !isAbsolute, '/', isPosixPathSeparator);
@@ -1543,8 +1540,8 @@ const posix = {
 
     // Get non-dir info
     for (; i >= start; --i) {
-      const code = StringPrototypeCharCodeAt(path, i);
-      if (code === CHAR_FORWARD_SLASH) {
+      const code = path[i];
+      if (code === '/') {
         // If we reached a path separator that was not part of a set of path
         // separators at the end of the string, stop now
         if (!matchedSlash) {
@@ -1559,7 +1556,7 @@ const posix = {
         matchedSlash = false;
         end = i + 1;
       }
-      if (code === CHAR_DOT) {
+      if (code === '.') {
         // If this is our first dot, mark it as the start of our extension
         if (startDot === -1)
           startDot = i;