[Refactor] make maybeUnwrapSymlink

Author: ljharb

lib/async.js

@@ -25,6 +25,17 @@ var defaultIsDir = function isDirectory(dir, cb) {
     });
 };
 
+var maybeUnwrapSymlink = function maybeUnwrapSymlink(x, opts, cb) {
+    if (opts && opts.preserveSymlinks === false) {
+        fs.realpath(x, function (realPathErr, realPath) {
+            if (realPathErr && realPathErr.code !== 'ENOENT') cb(realPathErr);
+            else cb(null, realPathErr ? x : realPath);
+        });
+    } else {
+        cb(null, x);
+    }
+};
+
 module.exports = function resolve(x, options, callback) {
     var cb = callback;
     var opts = options;
@@ -54,14 +65,14 @@ module.exports = function resolve(x, options, callback) {
     // ensure that `basedir` is an absolute path at this point, resolving against the process' current working directory
     var absoluteStart = path.resolve(basedir);
 
-    if (opts.preserveSymlinks === false) {
-        fs.realpath(absoluteStart, function (realPathErr, realStart) {
-            if (realPathErr && realPathErr.code !== 'ENOENT') cb(err);
-            else init(realPathErr ? absoluteStart : realStart);
-        });
-    } else {
-        init(absoluteStart);
-    }
+    maybeUnwrapSymlink(
+        absoluteStart,
+        opts,
+        function (err, realStart) {
+            if (err) cb(err);
+            else init(realStart);
+        }
+    );
 
     var res;
     function init(basedir) {

lib/sync.js

@@ -25,6 +25,19 @@ var defaultIsDir = function isDirectory(dir) {
     return stat.isDirectory();
 };
 
+var maybeUnwrapSymlink = function maybeUnwrapSymlink(x, opts) {
+    if (opts && opts.preserveSymlinks === false) {
+        try {
+            return fs.realpathSync(x);
+        } catch (realPathErr) {
+            if (realPathErr.code !== 'ENOENT') {
+                throw realPathErr;
+            }
+        }
+    }
+    return x;
+};
+
 module.exports = function (x, options) {
     if (typeof x !== 'string') {
         throw new TypeError('Path must be a string.');
@@ -42,17 +55,7 @@ module.exports = function (x, options) {
     opts.paths = opts.paths || [];
 
     // ensure that `basedir` is an absolute path at this point, resolving against the process' current working directory
-    var absoluteStart = path.resolve(basedir);
-
-    if (opts.preserveSymlinks === false) {
-        try {
-            absoluteStart = fs.realpathSync(absoluteStart);
-        } catch (realPathErr) {
-            if (realPathErr.code !== 'ENOENT') {
-                throw realPathErr;
-            }
-        }
-    }
+    var absoluteStart = maybeUnwrapSymlink(path.resolve(basedir), opts);
 
     if ((/^(?:\.\.?(?:\/|$)|\/|([A-Za-z]:)?[/\\])/).test(x)) {
         var res = path.resolve(absoluteStart, x);