Is it possible to make closing the app window Exit Watch Later?

[parasiteoflife]

I've set the shortkey to Exit Watch Later to Q, Ctrl+w and Ctrl+W, but I often just close the window clicking on the X button rather than pressing the shortkeys and I have been wondering this for a long time.
I would like to make every exit operation an Exit Watch Later one, so in short I always want to save the Watch Later status no matter how I close the application, can this be changed userwide or would it have to be a feature request?

EDIT: Here is the script I'm using:

msg = require 'mp.msg'

function shutdown()
    msg.info('saving watch later...')
    mp.command("write-watch-later-config")
end

mp.register_event('shutdown', shutdown)

[stax76]

This might be possible with a user script. You can try getting help with the code, asking on reddit.

There is a shutdown event.

When this event happens, it's possible to execute the input command write-watch-later-config.