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An example of how to implement AbortController in a function which returns Promise.
/* this function would return a Promise
* which would resolve with value `hello`
* after 4s
*/
function abortTask({ signal }) {
return new Promise((resolve, reject) => {
// 1. check if it's already aborted
if (signal && signal.aborted) {
return reject(new DOMException('`signal` is in `aborted` state', 'ABORT_ERR'));
}
// wait for 4s
setTimeout(() => resolve("hello"), 4000);
// 2. add a listener to `signal` to check its state
signal && signal.addEventListener('abort', () => {
// reject promise when signal.aborted changes to `true`
return reject(new DOMException('aborted by user', 'ABORT_ERR'));
})
})
}
/* DRIVER CODE */
let signal; // just so that I could re-use it
// when `signal.aborted` is `false`
const abortController_1 = new AbortController();
signal = abortController_1.signal;
abortTask({ signal })
.then(t => console.log(t)) // hello
.catch(e => console.error(e.message))
// when `signal.aborted` is `true`
const abortController_2 = new AbortController();
signal = abortController_2.signal;
abortController_2.abort();
abortTask({ signal })
.then(t => console.log(t))
.catch(e => console.error(e.message)) // err
// when user calls AbortController.abort()
const abortController_3 = new AbortController();
signal = abortController_3.signal;
// abort task in 2s
setTimeout(() => abortController_3.abort(), 2000);
abortTask({ signal })
.then(t => console.log(t))
.catch(e => console.error(e.message)) // err
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