Preserve the leading slashes of Windows UNC paths

index.js

@@ -27,6 +27,13 @@ module.exports = function(path, stripTrailing) {
     }
   }
 
+  // preserve the leading slashes of a UNC path (`\\server\share\...`),
+  // consistent with the win32 namespace prefixes handled above
+  if (prefix === '' && len > 2 && path[0] === '\\' && path[1] === '\\' && path[2] !== '\\' && path[2] !== '/') {
+    path = path.slice(2);
+    prefix = '//';
+  }
+
   var segs = path.split(/[/\\]+/);
   if (stripTrailing !== false && segs[segs.length - 1] === '') {
     segs.pop();

test.js

@@ -84,4 +84,22 @@ describe('normalize-path', function() {
       });
     });
   });
+  describe('windows UNC paths', function() {
+    var units = [
+      ['\\\\Server01\\user\\docs\\Letter.txt', '//Server01/user/docs/Letter.txt'],
+      ['\\\\server\\share\\file.css', '//server/share/file.css'],
+      ['\\\\localhost\\c$\\temp\\file.txt', '//localhost/c$/temp/file.txt'],
+      ['\\\\server\\share\\', '//server/share'],
+    ];
+
+    units.forEach(function(unit) {
+      it('should preserve the leading slashes of ' + unit[0], function() {
+        assert.equal(normalize(unit[0]), unit[1]);
+      });
+    });
+
+    it('should keep a trailing slash when stripTrailing is false', function() {
+      assert.equal(normalize('\\\\server\\share\\', false), '//server/share/');
+    });
+  });
 });