[英]Async await function not executing within an event listener
我正在嘗試調用 Trip Advisor API 並使用 async/await 函數返回一些數據。
async/await 函數定義在一個名為 req.js 的文件中,代碼如下:
const findRest = async (reviews, closed) => {
const respond = await fetch(
"https://tripadvisor1.p.rapidapi.com/restaurants/list-by-latlng?limit=30¤cy=EUR&distance=2&lunit=km&lang=en_US&latitude=53.3498&longitude=-6.2603",
{
method: "GET",
headers: {
"x-rapidapi-host": "tripadvisor1.p.rapidapi.com",
"x-rapidapi-key": "x-rapidapi-key"
}
}
);
if (respond.status === 200) {
let data = await respond.json();
let newData = await data.data;
let data1 = await newData.filter(
review => parseInt(review.num_reviews) >= reviews
);
let data2 = await data1.filter(close => close.is_closed == closed);
return data2;
} else {
throw new Error("Could not provide results within specified parameters");
}
};
當事件偵聽器通過單擊小表單中的按鈕觸發時,將調用此方法。 此代碼位於名為 app.js 的文件中,如下所示:
document.getElementById("subButton").addEventListener("click", function(e) {
const userReviews = parseInt(document.querySelector(".userRev").value);
const userClose = document.querySelector(".userClose").value;
e.preventDefault();
console.log("click");
console.log(e.target.id);
findRest(userReviews, userClose)
.then(data =>
data.forEach(element =>
console.log(
`${element.name} matches your search criterea and is located at ${element.address}
To make a booking, please call ${element.phone}`
)
)
)
.catch(err => console.log(err));
});
供參考的是這里的 HTML:
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8" />
<meta name="viewport" content="width=device-width,initial-scale=1" />
<title>API Tester</title>
<meta name="author" content="Phil My Glass" />
<meta
name="description"
content="An app to help me practice my API calling"
/>
</head>
<body>
<header>
<h1>What Restaurant?</h1>
</header>
<main>
<form id="form">
<input id="userRev" class="userRev" /><br />
<input id="userClose" class="userClose" />
<button id="subButton" class="subButton" type="submit">Find!</button>
</form>
</main>
</body>
<script src="req.js" type="text/Javascript"></script>
<script src="app.js" type="text/Javascript"></script>
</html>
當我在 app.js 文件中運行 findRest 函數時,但在事件偵聽器之外並作為靜態數據傳入參數時,它執行查找並將所有請求的數據打印到控制台。 一旦我嘗試在事件偵聽器中運行它,就沒有任何反應。 沒有返回的數據打印,沒有錯誤,這讓我很生氣。
就像我說的,它在事件偵聽器之外工作正常,但我嘗試將 forEach 更改為 map 並且仍然沒有返回任何內容。 有人可以幫忙嗎!
從評論和您的回復來看:沒有發生任何事情的原因是因為數據是一個空數組。 Array.forEach(callback)
僅在數組包含元素時執行回調。
它可能為空的原因是restaurant.is_closed
的過濾器可能需要一個布爾值,而您傳入一個字符串(輸入元素的值是一個字符串)。
最好使用復選框來查看它是否被選中。 否則,您必須查看字符串輸入是否與“真”或“假”匹配。
findRest
包含不必要的等待。 你應該把它定義為
async function findRest(reviews, closed) {
const response = await fetch(
"https://tripadvisor1.p.rapidapi.com/restaurants/list-by-latlng?limit=30¤cy=EUR&distance=2&lunit=km&lang=en_US&latitude=53.3498&longitude=-6.2603",
{
method: "GET",
headers: {
"x-rapidapi-host": "tripadvisor1.p.rapidapi.com",
"x-rapidapi-key": "x-rapidapi-key"
}
}
);
if (response.status === 200) {
// The only async call is casting the response to a JavaScript object
const json = await response.json();
console.log(json);
const data = json.data;
// Filtering the array is not async
return data.filter((restaurant) => {
// Adding some additional debugs to prove my hypothesis right
const hasEnoughReviews = restaurant.num_review >= reviews;
const isClosed = restaurant.is_closed === closed;
console.log(`review debug: ${typeof restaurant.num_review}, ${typeof reviews} -> output: ${hasEnoughReviews}`);
console.log(`closed debug: ${typeof restaurant.is_closed}, ${typeof closed} -> output: ${isClosed}`)
return hasEnoughReviews && isClosed
})
} else {
throw new Error("Could not provide results within specified parameters");
}
}
您還可以在 eventListener 回調中使用 async/await,創建更清晰的代碼
document.getElementById("subButton").addEventListener("click", async (e) => {
const userReviews = parseInt(document.querySelector(".userRev").value);
// Judging by the filter in the findRest, this should be a boolean?
const userClose = document.querySelector(".userClose").value;
e.preventDefault();
console.log("click");
console.log(e.target.id);
try {
const restaurants = await findRest(userReviews, userClose);
// I think your issue is that restaurants is an empty array
console.log(restaurants)
restaurants.forEach(restaurant => {
console.log(`${restaurant.name} matches your search criterea and is located at ${restaurant.address}
To make a booking, please call ${restaurant.phone}`)
})
} catch (err) {
console.log(err)
}
});
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