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Error in code example, Chapter 9, "Promise-Based Single Use Listener and AbortController"

pnts
Posts: 25
This code snippet throws an error when run:
import { once, EventEmitter } from 'events' import { setTimeout } from 'timers/promises' const sometimesLaggy = new EventEmitter() const ac = new AbortController() const { signal } = ac setTimeout(2000 * Math.random(), null, { signal }).then(() => { sometimesLaggy.emit('ping') }) setTimeout(500).then(() => ac.abort()) try { await once(sometimesLaggy, 'ping', { signal }) console.log('pinged!') } catch (err) { // ignore abort errors: if (err.code !== 'ABORT_ERR') throw err console.log('canceled') }
Error:
node:timers/promises:47 reject(new AbortError(undefined, { cause: signal?.reason })); ^ AbortError: The operation was aborted code: 'ABORT_ERR', [cause]: DOMException [AbortError]: This operation was aborted
If I don't pass the AbortSignal
instance to setTimeout()
it works as expected.
I guess what we really should do is to add an error handler like so:
setTimeout(2000 * Math.random(), null, { signal }).then(() => { sometimesLaggy.emit('ping') }).catch(() => console.log("Don't throw error on reject!");
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