How I want ES6 promises to work (sometimes).

gistfile1.txt

var p;
var stream;

function foo() {
  p = new Promise();
  stream  = TweakWidgets();
  stream.once('message', bar);
  return p;
}

function bar(data) {
  p.resolve(data);
}

foo().then(function() { /* Called after the widget has been tweaked. */ });