异步函数 - Firebase，文档事件监听器

Question

我一直收到以下错误Uncaught SyntaxError: await is only valid in async function。我试过在async 所在的地方移动，我到处找，找不到解决方案。提前致谢。

    document.addEventListener('click', async () => async function(e){
        if(e.target && e.target.id == 'update-order'){
            updateCart();
        }
    }, false);
    
    async function updateCart(){
        firebase.auth().onAuthStateChanged(firebaseUser => {
            let username = getUsername(firebaseUser);
            var databaseRef = firebase.database().ref();
            var foods = document.getElementsByClassName("food-name-id");
            for(let i = 0; i < foods.length; i++){
                let foodData = await queryDB('USERS/' + username + '/CART', 'NAME', foods[i].innerHTML);
                let foodKey = await queryDBKey('USERS/' + username + '/CART', 'NAME', foods[i].innerHTML);

                var postData = {
                    NAME: foodData.NAME,
                    QUANTITY: document.getElementById("quantity-" + foodKey).value,
                    CATEGORY: foodData.CATEGORY,
                    PRICE: foodData.PRICE,
                  };
                var newItemRef = databaseRef.child(username + "/CART/"+ foodKey);
                newItemRef.update(postData);
            }  
            

        });
    }

Answer 1

您在传递给onAuthStateChanged() 的回调函数中使用await，因此如果您想在其中使用await，则必须声明async。

firebase.auth().onAuthStateChanged(async (firebaseUser) => {