使用Javascript在Firebase中斷開循環

Question

我是初學者Firebase，無法打開循環。下面的代碼會查看配方產品和產品數量，如果庫存有足夠的產品來製作配方，則代碼會觸發警報，指出有足夠的產品，否則會觸發警報，說明庫存產品不是足夠。我想從其他方面打破循環，我該怎麼辦？

checkFirebase.orderByKey().limitToLast(20).on('child_added', function(snapshot){ 

    var productRecipe = snapshot.key; 
    var amountRecipe = snapshot.child("amount").val() * amountAdded; 

    if(productRecipe == productStock){ 

     if(amountRecipe <= amountStock){ 
      alert("The amount is enough."); 
     }else{ 
      alert("The quantity is not enough."); 
      break; 
     } 

    } 

}); 

Answer 1

如果要停止監聽child_added事件，你可以嘗試Off。

試試這個：

checkFirebase.orderByKey().limitToLast(20).on('child_added', function(snapshot){ 

    var productRecipe = snapshot.key; 
    var amountRecipe = snapshot.child("amount").val() * amountAdded; 

    if(productRecipe == productStock){ 

     if(amountRecipe <= amountStock){ 
      alert("The amount is enough."); 
     }else{ 
      alert("The quantity is not enough."); 
      checkFirebase.off('child_added');//stop listening to child_added event 
     } 

    } 

}); 

欲瞭解更多信息，請off閱讀firebase References#off Documentation