[fixed] empty query strings not being removed

Conflicts:
	package.json

Author: mhils

modules/PathUtils.js

@@ -1,5 +1,5 @@
 var invariant = require('react/lib/invariant');
-var merge = require('qs/lib/utils').merge;
+var objectAssign = require('object-assign');
 var qs = require('qs');
 
 var paramCompileMatcher = /:([a-zA-Z_$][a-zA-Z0-9_$]*)|[*.()\[\]\\+|{}^$]/g;
@@ -144,14 +144,14 @@ var PathUtils = {
     var existingQuery = PathUtils.extractQuery(path);
 
     if (existingQuery)
-      query = query ? merge(existingQuery, query) : existingQuery;
+      query = query ? objectAssign(existingQuery, query) : existingQuery;
 
     var queryString = qs.stringify(query, { arrayFormat: 'brackets' });
 
     if (queryString)
       return PathUtils.withoutQuery(path) + '?' + queryString;
 
-    return path;
+    return Path.withoutQuery(path);
   }
 
 };

modules/__tests__/PathUtils-test.js

@@ -319,6 +319,10 @@ describe('PathUtils.withQuery', function () {
     expect(PathUtils.withQuery('/path?a=b', { c: [ 'd', 'e' ] })).toEqual('/path?a=b&c%5B%5D=d&c%5B%5D=e');
   });
 
+  it('removes query string', function () {
+    expect(Path.withQuery('/a/b/c?a=b', { a: undefined })).toEqual('/a/b/c');
+  });
+
   it('handles special characters', function () {
     expect(PathUtils.withQuery('/path?a=b', { c: [ 'd#e', 'f&a=i#j+k' ] })).toEqual('/path?a=b&c%5B%5D=d%23e&c%5B%5D=f%26a%3Di%23j%2Bk');
   });

package.json

@@ -47,7 +47,8 @@
   },
   "dependencies": {
     "qs": "2.4.1",
-    "classnames": "1.1.x"
+    "classnames": "1.1.x",
+    "object-assign": "^2.0.0"
   },
   "tags": [
     "react",