Potential memory leak by only adding handlers

[ukstv]

Consider code in the README file:

const anySignal = require('any-signal')

const userController = new AbortController()
const timeoutController = new AbortController()

const combinedSignal = anySignal([userController.signal, timeoutController.signal])
combinedSignal.addEventListener('abort', () => console.log('Abort!'))

// Abort after 1 second
const timeoutId = setTimeout(() => timeoutController.abort(), 1000)

// The user or the timeout can now abort the action
await performSomeAction({ signal: combinedSignal })
clearTimeout(timeoutId)

After all the lines are executed, there are still event handlers attached to userController.signal and timeoutController.signal. There is no code that clears them. It all works fine if userController and timeoutController both are garbage collected after clearTimeout.

Let's consider the following code, where an AbortController is long-lived, along with its AbortSignal.

class Loader {
  shutdownController = new AbortController()

  async load(id: string, options: { signal: AbortSignal }) {
    const effectiveSignal = anySignal([this.shutdownController.signal, options.signal])
    await doSomething(effectiveSignal)
    return "Success!"
  }
}

On every call to load method, you'd add an event handler to this.shutdownController.signal. It never gets removed, which leads to some minor but very constant memory leak, as well as some annoying warnings, like libp2p/js-libp2p#900

Are you open to PRs fixing this?

[jacobheun]

Are you open to PRs fixing this?

Yes, feel free to open a PR. If you can include a test that validates the event handler cleanup that would be great

[jacobheun]

Fixed in #24. This has been released in [email protected]