diff --git a/src/util/query.js b/src/util/query.js
index b9abc211f..029fbd772 100644
--- a/src/util/query.js
+++ b/src/util/query.js
@@ -29,7 +29,7 @@ export function resolveQuery (
     parsedQuery = {}
   }
   for (const key in extraQuery) {
-    parsedQuery[key] = extraQuery[key]
+    parsedQuery[key] = extraQuery[key].toString()
   }
   return parsedQuery
 }
diff --git a/test/unit/specs/query.spec.js b/test/unit/specs/query.spec.js
index 22c1e6c74..1b8a18e6e 100644
--- a/test/unit/specs/query.spec.js
+++ b/test/unit/specs/query.spec.js
@@ -19,6 +19,11 @@ describe('Query utils', () => {
         arr: ['1', null, '2']
       })
     })
+
+    it('should cast query props into string', () => {
+      const query = resolveQuery('foo=bar&foo=k', { baz: 1 })
+      expect(typeof query.baz).toBe('string')
+    })
   })
 
   describe('stringifyQuery', () => {