ES next & Async Await
https://jestjs.io/docs/en/asynchronous#async-await
ES7
new
async () => {}
const f = async () => {
return 1;
};
f().then(value => console.log(value));
// 1
// Promise {<resolved>: undefined}
f();
// Promise {<resolved>: 1}
old
async function() {}
async function ff() {
return 1;
}
ff().then(alert);
// 1
//Promise {<resolved>: undefined}
ff().then(value => console.log(value));
// 1
// Promise {<resolved>: undefined}
Fetch API & Async Await
practical demo
const fetchJSON = (url = ``) => {
return fetch(url,
{
method: "GET",
// mode: "no-cors",
mode: "cors",
credentials: "same-origin",
headers: {
"Content-Type": "application/json; charset=utf-8",
},
})
.then(res => res.json())
.then(
(json) => {
return json;
}
)
.catch(err => console.log(`fetch error`, err));
};
// async / await
async function getDatas(url = ``) {
try {
return await fetchJSON(url);
} catch (err) {
console.error("getDatas error:
", err);
}
}
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