javascript - 使用 Javascript 在 Firebase 中中断循环

Question

我是 Firebase 初学者，在打破循环方面遇到了麻烦。下面的代码查看配方产品和产品数量，如果库存有足够的产品来制作配方，代码会触发警报，说明有足够的产品，否则会触发警报，说明库存产品不足足够的。我想打破 else 的循环，我该怎么做？

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

如果你想停止监听child_added事件，你可以试试Off。

试试这个:

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
        }

    }

});

有关off的更多信息，请阅读firebase References#off Documentation