如何将json对象数组添加到对象数组中？

For the json object :

对于json对象：

 var str={  
  "roles":[
            {
                "roleId":"Abcd",
                "envRoleName": "0101",
                "roleName": "Admin",
                "envCode":"HosJ",
                "envName":"UoH"
            },
            {
                "roleId":"efgh",
                "envRoleName": "0102",
                "roldeName": "User",
                "envCode":"HosJ",
                "envName":"HosJ"
            }
        ]
       }
 var str={