Rx.Observable.prototype.delayMinimumInterval: ensures a minimum interval between notifications.

delayMinimumInterval.js

Rx.Observable.prototype.delayMinimumInterval = function (relativeTime, scheduler) {
  if (scheduler === undefined) scheduler = Rx.Scheduler.timeout;

  var latest = scheduler.now();

  return this
    .selectMany(function (x) {
      var now = new Date(scheduler.now());
      var next = new Date(latest);
      next.setMilliseconds(next.getMilliseconds() + relativeTime);
      latest = next > now ? next : now;
      return Rx.Observable.returnValue(x).delay(latest, scheduler);
    });
};

example.js

var Rx = require('rx');

var a = Rx.Observable.interval(125).take(25);
var b = Rx.Observable.interval(75).take(25);

a.merge(b)
  .timeInterval()
  .delayMinimumInterval(100)
  .timeInterval()
  .select(function (x) {
    return {
      value: x.value.value,
      altered: x.interval,
      original: x.value.interval
    };
  })
  .subscribe(function (x) {
    console.log(x);
  });