fix(query): Fix query props should be casted into string (fix vuejs#2131)

Author: mohamed.gad

Diff for: 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 for: 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', () => {