我必须单击两次搜索按钮才能从api获取数据
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当我第一次单击搜索按钮时,它会出现两个错误:
- main.js:68获取https://cors-anywhere.herokuapp.com/https://api.darksky.net/forecast/API_key/ 404(未找到)
- 未捕获(在promise中)SyntaxError:位于0的JSON中的意外标记N.
但是当我第二次点击搜索按钮时,错误消失了。所以我必须单击两次搜索按钮才能从API获取数据。
的index.html
<form class="searchForm" method="POST">
<div class="form-div">
<label for="loaction">Enter a location</label>
<input type="text" class="searchForm-input" id="loaction" placeholder="Location">
<button type="submit">Search</button>
</div>
</form>
<div class="echo">--</div>
<div class="location">
<h1 class="location-timezone">Timezone</h1>
</div>
<div class="temperature">
<div class="degree-section">
<h2 class="temperature-degree">34</h2>
<span>F</span>
</div>
</div>
main.js
let lat1 = '';
let form = document.querySelector('.searchForm');
form.addEventListener('submit', handleSubmit);
function handleSubmit(event) {
event.preventDefault();
const input = document.querySelector('.searchForm-input').value;
// remove whitespace from the input
const searchQuery = input.split(' ').join('+');
// print `searchQuery` to the console
console.log(searchQuery);
let geocodeURL = `https://maps.googleapis.com/maps/api/geocode/json?
address=${searchQuery}&key=api_key`;
fetch(geocodeURL)
.then(response => {
return response.json();
})
.then(data => {
let max = data.results[0].geometry.location;
console.log(max);
let max1 = max.lat + ',' + max.lng;
console.log(max1);
lat1 = max1;
console.log(lat1);
})
console.log(geocodeURL);
let temperatureDegree = document.querySelector('.temperature-degree');
let locationTimezone = document.querySelector('.location-timezone');
let echos = document.querySelector('.echo');
echos.textContent = searchQuery;
const proxy = 'https://cors-anywhere.herokuapp.com/';
const api =
`${proxy}https://api.darksky.net/forecast/aki_key/${lat1}`;
fetch(api)
.then(response => {
return response.json();
})
.then(data => {
console.log(data);
const {temperature} = data.currently;
temperatureDegree.textContent = temperature;
locationTimezone.textContent = data.timezone;
})
}
答案
您有两个异步操作,第二个需要使用第一个AJAX操作的结果继续:
fetch(geocodeURL)
.then(response => {
return response.json();
})
.then(data => {
let max = data.results[0].geometry.location;
console.log(max);
let max1 = max.lat+',' + max.lng;
console.log(max1);
lat1 = max1; <-- lat1 is used in second AJAX call
console.log(lat1);
})
console.log(geocodeURL);
有些行后来:
const proxy = 'https://cors-anywhere.herokuapp.com/';
const api =
`${proxy}https://api.darksky.net/forecast/aki_key/${lat1}`; // <-- lat1 will be undefined
因此,当您单击搜索按钮时,第一个将触发,当它返回时,它将填充lat1
变量。因为这是Promise的结果,它会在它完成后立即触发,同时主线程将会继续并执行下一个fetch(api)
语句而不等待lat1
被设置。只需将第二个AJAX调用移动到Promise解析中:
event.preventDefault();
const input = document.querySelector('.searchForm-input').value;
// remove whitespace from the input
const searchQuery = input.split(' ').join('+');
// print `searchQuery` to the console
console.log(searchQuery);
let geocodeURL = `https://maps.googleapis.com/maps/api/geocode/json?
address=${searchQuery}&key=api_key`;
fetch(geocodeURL)
.then(response => {
return response.json();
})
.then(data => {
let max = data.results[0].geometry.location;
console.log(max);
let max1 = max.lat+',' + max.lng;
console.log(max1);
lat1 = max1;
console.log(lat1);
let temperatureDegree = document.querySelector('.temperature-
degree');
let locationTimezone = document.querySelector('.location-timezone');
let echos = document.querySelector('.echo');
echos.textContent = searchQuery;
const proxy = 'https://cors-anywhere.herokuapp.com/';
const api =
`${proxy}https://api.darksky.net/forecast/aki_key/${lat1}`;
fetch(api)
.then(response => {
return response.json();
})
.then(data => {
console.log(data);
const {temperature} = data.currently;
temperatureDegree.textContent = temperature;
locationTimezone.textContent = data.timezone;
})
}
})
console.log(geocodeURL);
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