Question

尝试使用Firebase并尝试获取动态添加的新添加的子项。我怎样才能检索：pi0usqkj16o？

var availability = database.ref("games/setup");
availability.once("value", function(snapshot){

    console.log(JSON.stringify( snapshot.val() ) );

});

snapshot.val()给了我以下内容：

{
    "pi0usqkj16o":{
        "player1":"ed",
        "player1Choice":"",
        "player1Wins":0,
        "player2":"",
        "player2Choice":"",
        "player2Wins":0,
        "total":0
    },
    "wpgnfq1swac":{
        "player1":"ed",
        "player1Choice":"",
        "player1Wins":0,
        "player2":"",
        "player2Choice":"",
        "player2Wins":0,
        "total":0
    }
}

最终目标是定位动态创建的新创建的目录（子）并给出序列号名称。也许做这样的事情？ var name = pi0usqkj16o; database.ref（＆＃34; somefolder /＆＃34; + name）; `

但是如何才能将上述json中的序列单独隔离？

//App Code

  //INITIALIZE FIREBASE
  firebase.initializeApp(config);
  var database = firebase.database();


  var Methods = {

  //Makes a new serial (ex. pi0usqkj16o)
  function uniqueId(){
              return Math.random().toString(36).substr(2, 16);
            }

  //checks if a game room is already available
  initialCheck: function(callback){
        var availability = database.ref("games/setup");
        availability.once("value", function(snapshot){

          //if there is no readily available room already created..create a new room 
          if(snapshot.numChildren() < 1){
            var gameName = uniqueId();

            availability.update({
              [gameName]: {player1: "ed", player2: "", player1Choice: "", player2Choice: "", player1Wins: 0, player2Wins: 0, total: 0}
            });
          }
          else{
            var room = snapshot.key;
            // Need to find the room name to be able to assign it to the user.
            console.log("room is: " + room );
          }
        });
}

Answer 1

为了获得那个EXACT键，必须有一些你可以轻松参考的独特数据。这是一个想法：

{
"pi0usqkj16o":{
    "player1":"ed",
    "player1Choice":"",
    "player1Wins":0,
    "player2":"",
    "player2Choice":"",
    "player2Wins":0,
    "total":0,
    "gameNumber":1
},
"wpgnfq1swac":{
    "player1":"ed",
    "player1Choice":"",
    "player1Wins":0,
    "player2":"",
    "player2Choice":"",
    "player2Wins":0,
    "total":0,
    "gameNumber":2
 }
}

我添加了一个游戏号码＆＃39;对于你的数据，每场比赛后应该是unqiue。现在要获得确切的密钥：

firebase.database().ref('games/setup').once("value", function(snapshot){
   var data = snapshot.val();
   if (data && snapshot.child('gameNumber').val() === '1'){
     console.log(snapshot.key);
   } else {
     console.log("no data"); 
   }
});

这应该返回您要查找的密钥。当然，你需要坐下来思考一种重新构建数据的方法，以便进行这样的查询。

也给这个读一读： https://firebase.google.com/docs/reference/js/firebase.database.DataSnapshot

Firebase JavaScript检索动态创建的子键？

1 个答案: