Amazon dynamodb 条件加压发电机B插件

我的DynamoDb表有下面的数据模式。我试图在input=name（例如：input=my-topic2）的条件下追加列表订阅者。“topics”列表中可能有许多映射，我需要搜索name=input的映射，并从中向该主题添加订阅者

  {
        “server-id”: “123345678”,
        “server-name”: “my-server”
        “topics”: [
            {
                “name”: “my-topic”,
                “subscribers”: []
            },
            {
                “name”: “my-topic2”,
                “subscribers”: [] //This is what I need to append on a condition that the input = “my-topic2”
            }
         ]
    }

我现在正在使用下面的赞歌，它附加了“我的主题”订阅者

params = {
      ExpressionAttributeNames: {
        "#T": "topics", 
        "#S": "subscribers"
      }, 
      ExpressionAttributeValues: {
        ":vals": [
          message.author.id
        ]
      }, 
      Key: {
        'server-id': serverID
      }, 
      ReturnValues: "ALL_NEW", 
      TableName: tableName,
      UpdateExpression: "SET #T[0].#S = list_append(#T[0].#S, :vals)"
    };