Javascript Fetch API - 如何将输出保存为对象（而不是 Promise）
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Javascript Fetch API - How to save output to variable as an Object (not the Promise)
提问by Vlasta Po
Please, how can I save output of fetch to a variable - to be able to work with it as with an object?
请问，如何将 fetch 的输出保存到变量中 - 以便能够像处理对象一样使用它？
Here is the code:
这是代码：
var obj;
fetch("url", {
method: "POST",
body: JSON.stringify({
"filterParameters": {
"id": 12345678
}
}),
headers: {"content-type": "application/json"},
//credentials: 'include'
})
.then(res => res.json())
.then(console.log)
The final console.logwill show an object. But when I tried to save it to variable .then(res => obj = res.json())than the console.log(obj)will not hold the Object, but the Promise.
最后console.log将显示一个对象。但是，当我试图把它保存到变量.then(res => obj = res.json())比console.log(obj)将不会持有的对象，但这个承诺。
Any idea please, how to turn it into an Object saved in the variable?
任何想法，如何将其转换为保存在变量中的对象？
回答by yuriy636
For a modern async/awaitapproach refer to @PrathameshMore's answer below
对于现代异步/等待方法，请参阅下面的@PrathameshMore 的回答
.json()is an async method (it returns a Promise itself), so you have to assign the parsed value in the next .then()
.json()是一个异步方法（它本身返回一个 Promise），所以你必须在下一个中分配解析的值 .then()
var obj;
fetch('https://jsonplaceholder.typicode.com/posts/1')
.then(res => res.json())
.then(data => obj = data)
.then(() => console.log(obj))回答by Prathamesh More
Instead of storing in a variable, create a function that will return data, and then store it in a variable. So It can accessible in your whole file.
不是存储在变量中，而是创建一个将返回数据的函数，然后将其存储在变量中。所以它可以在你的整个文件中访问。
async fetchExam(id) {
try {
const response = await fetch(`/api/exams/${id}`, {
method: 'GET',
credentials: 'same-origin'
});
const exam = await response.json();
return exam;
} catch (error) {
console.error(error);
}
}
Then call that function to get data
然后调用该函数获取数据
async renderExam(id) {
const exam = await fetchExam(id);
console.log(exam);
}
