Functional Reactive Programming (FRP)をjsで手書きするとこんな感じになるか。

FRP.js

require('allthemagicalstuff');

//event object constructor;
function event (target, eventName) {
  return {
    target: target
  , eventName: eventName
  };
};

/*
 * SIGNALS
 */
var MouseE , mouseS;
MouseE.clicks = event(document, 'click');
MouseS.position = function (e) { 
  return {x:e.pageX, y:pageY};
};

//under the hood
function sampleOn (ev, signal) {
  var samples = [];
  var signal = extend(function () {
    return samples;
  }, EventEmitter);
  ev.target.addEventListener(ev.eventName, function (e) {
    samples.push(signal(e));
    signal.fire('change');
  });
  return signal;
}

var clickLocations = sampleOn(MouseE.clicks, MouseS.position); //is a compound signal


//capture the scene
function scene (locs) {
  return map(drawPoint, locs);
};

function drawPoint (pt) {
  return canvas.point(pt.x, pt.y);
};

function lift (f, sig) {
  sig.addEventListener('change');
  f(sig());
}

scene(clickLocations);
lift(scene, clickLocations);