path: fix POSIX path.resolve() perf regression

PR-URL: #38064 Reviewed-By: Matteo Collina <[email protected]> Reviewed-By: Rich Trott <[email protected]> Reviewed-By: Michaël Zasso <[email protected]> Reviewed-By: Evan Lucas <[email protected]> Reviewed-By: Luigi Pinca <[email protected]> Reviewed-By: Ruben Bridgewater <[email protected]>

Author: mscdex

lib/path.js

@@ -23,7 +23,6 @@
 
 const{
  FunctionPrototypeBind,
- RegExp,
  StringPrototypeCharCodeAt,
  StringPrototypeIndexOf,
  StringPrototypeLastIndexOf,
@@ -48,6 +47,8 @@ const{
  validateString,
 }=require('internal/validators');
 
+constplatformIsWin32=(process.platform==='win32');
+
 functionisPathSeparator(code){
 returncode===CHAR_FORWARD_SLASH||code===CHAR_BACKWARD_SLASH;
 }
@@ -1011,24 +1012,29 @@ const win32 ={
 posix: null
 };
 
+constposixCwd=(()=>{
+if(platformIsWin32){
+// Converts Windows' backslash path separators to POSIX forward slashes
+// and truncates any drive indicator
+constregexp=/\\/g;
+return()=>{
+constcwd=StringPrototypeReplace(process.cwd(),regexp,'/');
+returnStringPrototypeSlice(cwd,StringPrototypeIndexOf(cwd,'/'));
+};
+}
+
+// We're already on POSIX, no need for any transformations
+return()=>process.cwd();
+})();
+
 constposix={
 // path.resolve([from ...], to)
 resolve(...args){
 letresolvedPath='';
 letresolvedAbsolute=false;
 
 for(leti=args.length-1;i>=-1&&!resolvedAbsolute;i--){
-letpath;
-if(i>=0){
-path=args[i];
-}else{
-const_=StringPrototypeReplace(
-process.cwd(),
-newRegExp(`\\${module.exports.sep}`,'g'),
-posix.sep
-);
-path=StringPrototypeSlice(_,StringPrototypeIndexOf(_,posix.sep));
-}
+constpath=i>=0 ? args[i] : posixCwd();
 
 validateString(path,'path');
 
@@ -1431,4 +1437,4 @@ posix.posix = win32.posix = posix;
 win32._makeLong=win32.toNamespacedPath;
 posix._makeLong=posix.toNamespacedPath;
 
-module.exports=process.platform==='win32' ? win32 : posix;
+module.exports=platformIsWin32 ? win32 : posix;