abortable-iterator
Make any iterator or iterable abortable via an AbortSignal
About
Example
import { abortableSource } from 'abortable-iterator'
async function main () {
// An example function that creates an async iterator that yields an increasing
// number every x milliseconds and NEVER ENDS!
const asyncCounter = async function * (start, delay) {
let i = start
while (true) {
yield new Promise(resolve => setTimeout(() => resolve(i++), delay))
}
}
// Create a counter that'll yield numbers from 0 upwards every second
const everySecond = asyncCounter(0, 1000)
// Make everySecond abortable!
const controller = new AbortController()
const abortableEverySecond = abortableSource(everySecond, controller.signal)
// Abort after 5 seconds
setTimeout(() => controller.abort(), 5000)
try {
// Start the iteration, which will throw after 5 seconds when it is aborted
for await (const n of abortableEverySecond) {
console.log(n)
}
} catch (err) {
if (err.code === 'ERR_ABORTED') {
// Expected - all ok :D
} else {
throw err
}
}
}
main()
Install
$ npm i abortable-iterator
Browser <script> tag
Loading this module through a script tag will make its exports available as AbortableIterator in the global namespace.
<script src="https://unpkg.com/abortable-iterator/dist/index.min.js"></script>
API
import {
abortableSource,
abortableSink,
abortableTransform,
abortableDuplex
} from 'abortable-iterator'
abortableSource(source, signal, [options])
(alias for abortable.source(source, signal, [options]))
Make any iterator or iterable abortable via an AbortSignal.
Parameters
| Name | Type | Description |
|---|
| source | Iterable|Iterator | The iterator or iterable object to make abortable |
| signal | AbortSignal | Signal obtained from AbortController.signal which is used to abort the iterator. |
| options | Object | (optional) options |
| options.onAbort | Function | An (async) function called when the iterator is being aborted, before the abort error is thrown. Default null |
| options.abortMessage | String | The message that the error will have if the iterator is aborted. Default "The operation was aborted" |
| options.abortCode | String|Number | The value assigned to the code property of the error that is thrown if the iterator is aborted. Default "ABORT_ERR" |
| options.returnOnAbort | Boolean | Instead of throwing the abort error, just return from iterating over the source stream. |
| options.onReturnError | Function | When a generator is aborted, we call .return on it - if this function errors the error value will be passed to the .onReturnError callback if passed. Default null |
Returns
| Type | Description |
|---|
Iterable | An iterator that wraps the passed source parameter that makes it abortable via the passed signal parameter. |
The returned iterator will throw an AbortError when it is aborted that has a type with the value aborted and code property with the value ABORT_ERR by default.
abortableSink(sink, signal, [options])
The same as abortable.source except this makes the passed sink abortable. Returns a new sink that wraps the passed sink and makes it abortable via the passed signal parameter.
abortableTransform(transform, signal, [options])
The same as abortable.source except this makes the passed transform abortable. Returns a new transform that wraps the passed transform and makes it abortable via the passed signal parameter.
abortableDuplex(duplex, signal, [options])
The same as abortable.source except this makes the passed duplex abortable. Returns a new duplex that wraps the passed duplex and makes it abortable via the passed signal parameter.
Note that this will abort both sides of the duplex. Use duplex.sink = abortable.sink(duplex.sink) or duplex.source = abortable.source(duplex.source) to abort just the sink or the source.
Related
it-pipe Utility to "pipe" async iterables together
API Docs
License
Licensed under either of
Contribution
Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.
