@byungi/p-cancel

A cancelable promise.

Example

1import PCancel, {CancelError} from '@byungi/p-cancel'
2
3const requestPromise = new PCancel((resolve, reject, onCancel) => {
4    var xhr = new XMLHttpRequest();
5    xhr.on('load', resolve);
6    xhr.on('error', reject);
7    xhr.open('GET', 'http://delay/500ms/call', true);
8    xhr.send(null);
9
10    onCancel(()=> xhr.abort())
11})
12
13console.log(requestPromise.isCanceled) // => false
14
15setTimeout(()=> {
16    requestPromise.cancel() // => After 100ms, xhr is aborted.
17}, 100)
18
19requestPromise.catch(err => {
20    console.log(err.isCanceled) // => true
21    console.log(err instanceof CancelError) // => true
22    console.log(requestPromise.isCanceled) // => true
23})

API

new PCancel(executor)

PCancel is a promise implementation. Same as promise creation except for onCancel. onCancel receives a function to operate on cancel().

1const promise = new PCancel((resolve, reject, onCancel) => {
2    const timerId = setTimeout(lazyJob, 1000)
3    onCancel(()=> clearTimeout(timerId))
4})

promise.cancel([reason])

Execute the cancel operation added with onCancel and throw a CancelError.

promise.isCanceled

Returns whether the promise is canceled.

promise.pipe(onFulfilled, onRejected)

Similar to then but can propagate cancel to the upper promise.

1const handleWithRequestPromise = requestPromise.pipe(response => {
2    handleResponse(response)
3})
4
5handleWithRequestPromise.cancel() // => xhr is aborted

License

MIT