Meteor predates Promises and Async/Await. You have to remember at the time all you had was callbacks and async.js to manage them. There was Bluebird around 2014 but Meteor was even before that. Meteor uses node-fiber, I assume it still does, but it was very "non-standard" at the time and definitely now. You rarely saw it in any codebase.
I’m well aware of Fibers, and the big async API kerfuffle of 200*s! I was amused to see Q pop up unmentioned in git blames just today. I’d be curious if Fibers would find adoption if it were introduced today. I suspect yes, with much regret because knowing when functions suspend is not something people would give up knowing the implications.
