Abort 

Help to write code accepting an abortSignal.

- Designed to cleanup by default (removing event listeners, clearing timeouts, ...)
- Allow to safely bypass max listeners warning when needed
- Code can do 20 abortable fetch requests in parallel without warnings
- Manage multiple abort signals
- Compose abort signals from multiple sources
- Code can do differents things depending on which signal aborted the operation

Example

_fetch_demo.mjs_

``js
import { customFetch } from "./fetch_custom.mjs";

const abortController = new AbortController();
const signal = abortController.signal;
process.on("warning", () => {
abortController.abort();
});
await customFetch("http://example.com", { signal });
`

Code above pass an abort signal to customFetch.

Let's see how "@jsenv/abort" helps to manage the signal received.

_fetch_custom.mjs_

`js
import { Abort } from "@jsenv/abort"

export const customFetch = (
url,
{ signal = new AbortController().signal } = {},
) => {
// create an operation
const fetchOperation = Abort.startOperation()

// abort according to signal received in param
fetchOperation.addAbortSignal(signal)

// also abort on SIGINT
const SIGINTAbortSource = fetchOperation.addAbortSource((abort) => {
process.on("SIGINT", abort)
return () => {
process.removeListener("SIGINT", abort)
}
})

// also abort after 5s
const timeoutAbortSource = fetchOperation.timeout(5000)

try {
const response = await fetch(url, { signal: fetchOperation.signal })
return response
} catch (e) {
if (Abort.isAbortError(e)) {
if (SIGINTAbortSource.signal.aborted) {
// aborted by SIGINT
}
if (timeoutAbortSource.signal.aborted) {
// aborted by timeout
}
if (signal.aborted) {
// aborted from outside
}
}
throw e
} finally {
await fetchOperation.end()
}
}
``