异步/伺机没有结合工作与取 [英] async / await not working in combination with fetch
问题描述
我试图用ES7 异步 / 等待与一起取。我知道我接近，但我不能让它工作。这里是code：
类吧{
异步负载（）{
让URL ='https://finance.yahoo.com/webservice/v1/symbols/goog/quote?format=json';
尝试{
响应=等待获取（URL）;
返回response.responseText;
}赶上（E）{
返回e.message;
}
}
}
这是我使用方法如下：
让巴=新的酒吧（）;
bar.load（）。然后（功能（VAL）{
的console.log（VAL）;
}）;
由于某种原因，我总是进入抓的消息
没有定义响应
任何建议我做什么错了？
更新：由于在评论中暗示，它可能是与问题获取，所以我尝试简化（ES5）版本：
＆LT;！DOCTYPE HTML＆GT;＆LT; HTML和GT;
＆LT; HEAD＆GT;
＆LT;脚本＆GT;
VAR URL ='https://finance.yahoo.com/webservice/v1/symbols/goog/quote?format=json';
取（URL，{方法：'得到'，模式：CORS'}），然后（功能（响应）{
的console.log（response.responseText）;
}）;
＆LT; / SCRIPT＆GT;
＆LT; HEAD＆GT; ＆LT;身体GT;＆LT; /身体GT;
＆LT; HTML和GT;
和仍然没有工作:(不过，如果我更换取它的工作原理：
VAR要求=新XMLHtt prequest（）;
request.open（GET，网址，虚假的）;
request.send（NULL）;
的console.log（request.responseText）;
您忘了申报响应作为一个变量。类code是始终严格code，并且不会分配给的 implictly全局变量的。相反，它抛出一个的ReferenceError 。
除此之外， 响应 对象没有像XHR一个的responseText 财产，他们有一个的.text（）方法该等待要接收的身体，并返回一个承诺
类吧{
异步负载（）{
让URL ='https://finance.yahoo.com/webservice/v1/symbols/goog/quote?format=json';
尝试{
让我们响应=的await获取（URL）;
// ^^^^
返回伺机response.text（）;
// ^^^^^^
}赶上（E）{
返回e.message;
}
}
}
I'm trying to use ES7 async / await together with fetch. I know I'm close but I can't get it to work. Here is the code:
class Bar {
async load() {
let url = 'https://finance.yahoo.com/webservice/v1/symbols/goog/quote?format=json';
try {
response = await fetch(url);
return response.responseText;
} catch (e) {
return e.message;
}
}
}
which I use as follows:
let bar = new Bar();
bar.load().then(function (val) {
console.log(val);
});
For some reason I always get into the catch with the message
response is not defined
Any suggestions what I do wrong ?
UPDATE: As suggested in the comments, it might be an issue with fetch, so I tried a simplified (ES5) version:
<!doctype html>
<html>
<head>
<script>
var url = 'https://finance.yahoo.com/webservice/v1/symbols/goog/quote?format=json';
fetch(url, {method: 'get', mode: 'cors'}).then(function (response) {
console.log(response.responseText);
});
</script>
<head>
<body></body>
<html>
And still doesn't work :( However, if I replace fetch it works:
var request = new XMLHttpRequest();
request.open("GET", url, false);
request.send(null);
console.log(request.responseText);
You forgot to declare response as a variable. Class code is always strict code, and you won't get away with assigning to implictly global variables. Instead, it throws a ReferenceError.
Apart from that, Response objects don't have a responseText property like a XHR, they do have a .text() method that waits for the body to be received and returns a promise.
class Bar {
async load() {
let url = 'https://finance.yahoo.com/webservice/v1/symbols/goog/quote?format=json';
try {
let response = await fetch(url);
// ^^^^
return await response.text();
// ^^^^^^
} catch (e) {
return e.message;
}
}
}
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