配置表的判定写法.

 

当GameData.map[arr[0]] 没有值是 等于{},有值时等于GameData.map[arr[0]] .

GameData.map[arr[0]] = GameData.map[arr[0]] || {}  

  

GameData.map[arr[0]] = GameData.map[arr[0]] || {}   =if(GameData.map[arr[0]]=null,){

GameData.map[arr[0]]={}

}else{

GameData.map[arr[0]]=GameData.map[arr[0]]

}