path: refactor code for clarity

This moves a condition inside of a for loop which can only be triggered at the very end of the for loop outside of the loop. That way the for loop itself is much simpler and easier to understand and the code itself is less indented which should increase the readability. It also refactors some `var` to `let` and `const`. PR-URL: #25278 Reviewed-By: Michaël Zasso <[email protected]>
nodejs · Mar 1, 2019 · 5b8ac58 · 5b8ac58
1 parent 348f1fb
commit 5b8ac58
Showing 1 changed file with 63 additions and 65 deletions.
diff --git a/lib/path.js b/lib/path.js
@@ -478,47 +478,46 @@ const win32 = {
     const toLen = toEnd - toStart;
 
     // Compare paths to find the longest common path from root
-    var length = (fromLen < toLen ? fromLen : toLen);
-    var lastCommonSep = -1;
-    var i = 0;
-    for (; i <= length; ++i) {
-      if (i === length) {
-        if (toLen > length) {
-          if (to.charCodeAt(toStart + i) === CHAR_BACKWARD_SLASH) {
-            // We get here if `from` is the exact base path for `to`.
-            // For example: from='C:\\foo\\bar'; to='C:\\foo\\bar\\baz'
-            return toOrig.slice(toStart + i + 1);
-          } else if (i === 2) {
-            // We get here if `from` is the device root.
-            // For example: from='C:\\'; to='C:\\foo'
-            return toOrig.slice(toStart + i);
-          }
-        }
-        if (fromLen > length) {
-          if (from.charCodeAt(fromStart + i) === CHAR_BACKWARD_SLASH) {
-            // We get here if `to` is the exact base path for `from`.
-            // For example: from='C:\\foo\\bar'; to='C:\\foo'
-            lastCommonSep = i;
-          } else if (i === 2) {
-            // We get here if `to` is the device root.
-            // For example: from='C:\\foo\\bar'; to='C:\\'
-            lastCommonSep = 3;
-          }
-        }
-        break;
-      }
-      var fromCode = from.charCodeAt(fromStart + i);
-      var toCode = to.charCodeAt(toStart + i);
-      if (fromCode !== toCode)
+    const length = fromLen < toLen ? fromLen : toLen;
+    let lastCommonSep = -1;
+    let i = 0;
+    for (; i < length; i++) {
+      const fromCode = from.charCodeAt(fromStart + i);
+      if (fromCode !== to.charCodeAt(toStart + i))
         break;
       else if (fromCode === CHAR_BACKWARD_SLASH)
         lastCommonSep = i;
     }
 
     // We found a mismatch before the first common path separator was seen, so
     // return the original `to`.
-    if (i !== length && lastCommonSep === -1) {
-      return toOrig;
+    if (i !== length) {
+      if (lastCommonSep === -1)
+        return toOrig;
+    } else {
+      if (toLen > length) {
+        if (to.charCodeAt(toStart + i) === CHAR_BACKWARD_SLASH) {
+          // We get here if `from` is the exact base path for `to`.
+          // For example: from='C:\\foo\\bar'; to='C:\\foo\\bar\\baz'
+          return toOrig.slice(toStart + i + 1);
+        }
+        if (i === 2) {
+          // We get here if `from` is the device root.
+          // For example: from='C:\\'; to='C:\\foo'
+          return toOrig.slice(toStart + i);
+        }
+      }
+      if (fromLen > length) {
+        if (from.charCodeAt(fromStart + i) === CHAR_BACKWARD_SLASH) {
+          // We get here if `to` is the exact base path for `from`.
+          // For example: from='C:\\foo\\bar'; to='C:\\foo'
+          lastCommonSep = i;
+        } else if (i === 2) {
+          // We get here if `to` is the device root.
+          // For example: from='C:\\foo\\bar'; to='C:\\'
+          lastCommonSep = 3;
+        }
+      }
     }
 
     let out = '';
@@ -1079,41 +1078,40 @@ const posix = {
     const toLen = (toEnd - toStart);
 
     // Compare paths to find the longest common path from root
-    var length = (fromLen < toLen ? fromLen : toLen);
-    var lastCommonSep = -1;
-    var i = 0;
-    for (; i <= length; ++i) {
-      if (i === length) {
-        if (toLen > length) {
-          if (to.charCodeAt(toStart + i) === CHAR_FORWARD_SLASH) {
-            // We get here if `from` is the exact base path for `to`.
-            // For example: from='/foo/bar'; to='/foo/bar/baz'
-            return to.slice(toStart + i + 1);
-          } else if (i === 0) {
-            // We get here if `from` is the root
-            // For example: from='/'; to='/foo'
-            return to.slice(toStart + i);
-          }
-        } else if (fromLen > length) {
-          if (from.charCodeAt(fromStart + i) === CHAR_FORWARD_SLASH) {
-            // We get here if `to` is the exact base path for `from`.
-            // For example: from='/foo/bar/baz'; to='/foo/bar'
-            lastCommonSep = i;
-          } else if (i === 0) {
-            // We get here if `to` is the root.
-            // For example: from='/foo'; to='/'
-            lastCommonSep = 0;
-          }
-        }
-        break;
-      }
-      var fromCode = from.charCodeAt(fromStart + i);
-      var toCode = to.charCodeAt(toStart + i);
-      if (fromCode !== toCode)
+    const length = (fromLen < toLen ? fromLen : toLen);
+    let lastCommonSep = -1;
+    let i = 0;
+    for (; i < length; i++) {
+      const fromCode = from.charCodeAt(fromStart + i);
+      if (fromCode !== to.charCodeAt(toStart + i))
         break;
       else if (fromCode === CHAR_FORWARD_SLASH)
         lastCommonSep = i;
     }
+    if (i === length) {
+      if (toLen > length) {
+        if (to.charCodeAt(toStart + i) === CHAR_FORWARD_SLASH) {
+          // We get here if `from` is the exact base path for `to`.
+          // For example: from='/foo/bar'; to='/foo/bar/baz'
+          return to.slice(toStart + i + 1);
+        }
+        if (i === 0) {
+          // We get here if `from` is the root
+          // For example: from='/'; to='/foo'
+          return to.slice(toStart + i);
+        }
+      } else if (fromLen > length) {
+        if (from.charCodeAt(fromStart + i) === CHAR_FORWARD_SLASH) {
+          // We get here if `to` is the exact base path for `from`.
+          // For example: from='/foo/bar/baz'; to='/foo/bar'
+          lastCommonSep = i;
+        } else if (i === 0) {
+          // We get here if `to` is the root.
+          // For example: from='/foo'; to='/'
+          lastCommonSep = 0;
+        }
+      }
+    }
 
     var out = '';
     // Generate the relative path based on the path difference between `to`