Javascript 当数据作为json对象通过EJS和节点中的表单提交时，访问对象值

我试图访问路由文件中的数据，该文件是通过EJS视图中的表单提交的。有了这个房间的详细信息，我将带着房间id和房间名称转到下一条路线。问题是返回对象是字符串，无法转换为JSON

如何访问Json对象室及其值，如room.\u id，room.roomName

欢迎光临

        <form action="/chat" method="post">
            <div class="form-control">
                <label for="username">Display Name</label>
                <input type="text" name="username" id="username" placeholder="Enter username..." value="<%= name %>" required />
            </div>
            <div class="form-control">
                <label for="room">Room</label>
                <select name="room" id="room">                                                            
                    <% rooms.forEach(function(room){ %> 
                    <option value="<%= room %>" data-roomid="<%= room._id %>" data-roomtype="<%= room.roomType %>"><%= room.roomName %></option>
                    <%  }); %>                    
                </select>
            </div>
            <div class="form-control">                    
                <input type="hidden" name="email" value="<%= email %>" />
                <input type="hidden" name="img" value="<%= img %>" />
                <input type="hidden" name="googleId" value="<%= googleId %>" />
                <input type="hidden" name="userId" value="<%= userId %>" />
            </div>
            <button type="submit" class="btn">Join Chat</button>
        </form>        

我有控制台的输出，这将更容易理解什么发生在后台

postdata room  { _id: 5f4f3662cb74553d5e03d076,
  roomName: 'PHP',
  roomType: 'public' }
room  "{ _id: 5f4f3662cb74553d5e03d076,\r\n  roomName: 'PHP',\r\n  roomType: 'public' }"
string
room obj  { _id: 5f4f3662cb74553d5e03d076,
  roomName: 'PHP',
  roomType: 'public' }

postdata room  { _id: 5f4f3662cb74553d5e03d076,
  roomName: 'PHP',
  roomType: 'public' }
room  "{ _id: 5f4f3662cb74553d5e03d076,\r\n  roomName: 'PHP',\r\n  roomType: 'public' }"
string
room obj  { _id: 5f4f3662cb74553d5e03d076,
  roomName: 'PHP',
  roomType: 'public' }