I'm working with the example project provided in the "get started" tutorial on the Facebook messenger API docs. I've been able to get the project working and can respond to messages but I can't figure out how to send a message to a user. My problem is that I can't figure out how to get the user's ID before they send the bot a message. Is it possible to get this info upon their opening the window? Can I just generically populate every opened chat window with a message?
There is an npm package that handles this for you: