waitforit.js

// Optional `options.  Stuff like retry count, ramp-up, etc.
// should have sane defaults.
var wait = waitforit(options, function (cb) {
  // This would be the 'test' function.
  // cb(true) when 'it' is done.
});

wait.on('ready', function () {
  // Do something because the test condition passed.  
});

wait.on('timeout', function () {
  // We got past the max retries or max total time or w/e.  
});