JS:变量返回undefined，只是在前面定义了它
JS:变量返回undefined，只是在前面定义了它
提问于 2020-04-13 05:35:44
我的代码是
var api_url
$.getJSON("https://api.ipify.org/?format=json", function(e) {
myIP = e.ip;
//api_url = "https://cors-anywhere-ctrack.herokuapp.com/https://tools.keycdn.com/geo.json?host=" + myIP
});
//api_url = "https://cors-anywhere-ctrack.herokuapp.com/https://tools.keycdn.com/geo.json?host=" + myIP
function geoloc() {
api_url = "https://cors-anywhere-ctrack.herokuapp.com/https://tools.keycdn.com/geo.json?host=" + myIP
console.log(api_url)
const response = await fetch(api_url)
const data = await response.json();
console.log(data)
}
geoloc();我用Python3的http.server启动了它，它打印了"https://cors-anywhere-ctrack.herokuapp.com/https://tools.keycdn.com/geo.json?host=undefined"，不出所料，获取失败了。经过仔细检查，定义了变量myIP。我觉得这和async和await有关，但我不确定。
回答 2
Stack Overflow用户
回答已采纳
发布于 2020-04-13 05:39:40
https://jsfiddle.net/Lyjkzqcf/
您可以在$.getJSON()方法中调用geoloc()。请看下图：
var api_url
$.getJSON("https://api.ipify.org/?format=json", function(e) {
myIP = e.ip;
geoloc();
//api_url = "https://cors-anywhere-ctrack.herokuapp.com/https://tools.keycdn.com/geo.json?host=" + myIP
});
//api_url = "https://cors-anywhere-ctrack.herokuapp.com/https://tools.keycdn.com/geo.json?host=" + myIP
async function geoloc() {
api_url = "https://cors-anywhere-ctrack.herokuapp.com/https://tools.keycdn.com/geo.json?host=" + myIP
console.log(api_url)
const response = await fetch(api_url)
const data = await response.json();
console.log(data)
}<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
Stack Overflow用户
发布于 2020-04-13 05:42:50
试一试
async function geoloc() {
api_url = "https://cors-anywhere-ctrack.herokuapp.com/https://tools.keycdn.com/geo.json?host=" + myIP
console.log(api_url)
const response = await fetch(api_url)
const data = response.json();
console.log(data)
}仅将函数声明为async和await一次。
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原文链接：
https://stackoverflow.com/questions/61178480
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