feat: add signal option to dialog.showMessageBox - #26102

I don't love this ID system. Perhaps we could use something like AbortSignal? https://w3ctag.github.io/design-principles/#aborting

I don't love this ID system. Perhaps we could use something like AbortSignal? https://w3ctag.github.io/design-principles/#aborting

I did not know it exists, it is a better design than a custom ID system. So I think the new API would look like this?

const controller = new AbortController();
dialog.showMessageBox(win, {
  signal: controller.signal,
  message: 'message',
})

controller.abort();

There are 2 downsides though:

1. AbortController is a currently DOM only thing. Node is adding its own AbortController since v15, but it is currently marked experimental and not supported by any promise API, using it seems a bit risky.
2. It can only be used to cancel the task, and does not provide a way to specify options. We might want to extend the API in future.

So I think maybe we can invent our own AbortController style API:

const controller = new dialog.MessageBoxAbortController()

dialog.showMessageBox(win, {
  signal: controller.signal,
  message: 'message',
})

controller.abort();
// future extensions.
controller.close({button: 1})

I'm not convinced we need the option to "pretend" that a particular button was pressed. User code can handle that plumbing by itself if needed, e.g.

const controller = new AbortController()
let abortedSignal = null

dialog.showMessageBox(win, {
  signal: controller.signal,
  message: 'message'
}).then(status => {
  if (status == null)
    status = abortedSignal
})

abortedSignal = 1
controller.abort();

as for Node adding its own, it seems like they are planning to match the DOM implementation (similar to their implementation of URL). The DOM version is standardized, so it seems pretty safe to build our own shim that matches that and switch to Node's once it's available.

I'm going to wait for the next major upgrade of Node in Electron, adding typescript declarations for our own AbortSignal is going to have problems like node-fetch/node-fetch#741.

I have updated this PR to use AbortSignal as option.

Release Notes Persisted

Add signal option to dialog.showMessageBox.

I was unable to backport this PR to "14-x-y" cleanly;
you will need to perform this backport manually.

@MarshallOfSound The AbortSignal was only added since Node 15, so this can not be back ported to Electron 14.