javascript - 如何向此嵌套 JSON 对象添加追加

Question

我的 JSON 对象是

"msg"=[{"userName":"Mandy","emailId":"m@t.co","userCreated":"2011-12-21 17:21:49","allowedDownloads":"15"},{"userName":"Andy","emailId":"ab@r.co","userCreated":"2011-12-21 17:29:58","allowedDownloads":"45"},{"userName":"Randy","emailId":"re@t.co","userCreated":"2012-01-02 10:18:19","allowedDownloads":"15"},{"userName":"Vandy","emailId":"vai@t.co","userCreated":"2012-01-02 15:49:20","allowedDownloads":"14"},{"userName":"Sandy","emailId":"vrush@t.co","userCreated":"2012-01-02 16:47:35","allowedDownloads":"14"}]

1)如何再添加 1 个人以便附加“msg”

{"userName":"Wendy","emailId":"w@t.co","userCreated":"2012-12-21 17:21:49","allowedDownloads":"15"}

2)如何向每个索引添加属性“爱好”，以便我拥有，例如<​​/p>

{"userName":"Wendy","emailId":"w@t.co","userCreated":"2012-12-21 17:21:49","allowedDownloads":"15","hobbies":"skiing,football,hockey"}

3) 如何查看索引“Wendy”是否有爱好“曲棍球”？

Answer 1

因为你有一个 Javascript 数组

  var msg = [{"userName":"Mandy","emailId":"m@t.co","userCreated":"2011-12-21 17:21:49","allowedDownloads":"15"},
             {"userName":"Andy","emailId":"ab@r.co","userCreated":"2011-12-21 17:29:58","allowedDownloads":"45"},
             {"userName":"Randy","emailId":"re@t.co","userCreated":"2012-01-02 10:18:19","allowedDownloads":"15"},
             {"userName":"Vandy","emailId":"vai@t.co","userCreated":"2012-01-02 15:49:20","allowedDownloads":"14"},
             {"userName":"Sandy","emailId":"vrush@t.co","userCreated":"2012-01-02 16:47:35","allowedDownloads":"14"}];

您可以轻松推送新元素

  msg.push({"userName":"Wendy","emailId":"w@t.co","userCreated":"2012-12-21 17:21:49","allowedDownloads":"15"});

但是要更新记录，您必须循环

  function update(username, property, value){

      for(var i=0; i < msg.length; i++){
          var user = msg[i];
          if(user["userName"] == username){
              user[property] = value;
              break;
          }          
      }

  }

要搜索，您还必须循环

  function check(username, property, value){

        for(var i=0; i < msg.length; i++){
            var user = msg[i];
            if(user["userName"] == username){
                var propertyVal = user[property];
                if( propertyVal && propertyVal.indexOf(value) != -1){
                    return true;
                }
            }          
        }
        return false;
    }