await 包装器以便在没有try-catch的情况下更容易地处理错误
await 包装器以便在没有try-catch的情况下更容易地处理错误
JavaScript 其它杂项
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详细介绍
await-of
About
ES7 async/await
gives to developers ability to write asynchronous code that look like synchronous. But under the hood it is still just a sugar on top of the ES6 Promise
.
You can write code that looks clean, but only unless you have to catch errors. To catch thrown error or handle the promise's rejection you have to surround it with try-catch
block or fallback to pure promises and from that moment visual purity of your code is over.
But there is a solution!
I really like the way it's done in Go. It has no error throwing mechanism, but has a multi-value return and the common way to handle errors in Go is to return error as a last value, like so:
data, err := someErrorFunc(someStuff)
if err != nil {
return err
}
But JavaScript has no multi-value return! - you would say. Sad, but true.
But!
It has a destructuring assignment and await-of
gives you ability to do this:
import of from "await-of";
async () => {
let [res, err] = await of(axios.get("some.uri/to/get"));
if (err) {
// rethrow if its not an axios response error
if (!err.response) {
throw err;
}
res = err.response;
}
const { data, status = 0 } = res;
console.log(data, status);
};
There is no modifications needed in function/promise you want to await - just pass it to the of()
and whole the magic will be done.
Installation
npm i --save await-of
Usage
import of from "await-of";
async function someAsyncStuff() {
let error, data;
// if we don't want to handle error
[data] = await of(Promise.reject("ERROR!"));
console.log(data); // undefined
// if promise was rejected - it's rejection value will be treated as error
[, error] = await of(Promise.reject("ERROR!"));
console.log(error); // ERROR!
// or if promise has any uncaught errors it'll catch them too!
[, error] = await of(
new Promise(() => {
throw new TypeError("ERROR!");
})
);
console.log(error.message); // ERROR!
}
Tests
# install dependencies if you haven't yet
npm install
npm run test