在Bacon.js中实现数字微调器

<script src="bacon.js"></script>

var increaseButton = document.getElementById('increaseButton');
var decreaseButton = document.getElementById('decreaseButton');

var increaseStream = Bacon.fromEvent(increaseButton, 'click');
var decreaseStream = Bacon.fromEvent(decreaseButton, 'click');

var valueBus = new Bacon.Bus();

var increaseValueStream = increaseStream.map(1);
var decreaseValueStream = decreaseStream.map(-1);

var valueStream = Bacon.mergeAll(increaseValueStream, decreaseValueStream)
  .scan(0, function (acc, value) {
    return acc + value;
  });

valueStream.onValue(function (value) {
  valueBus.push(value);
});

valueBus.onValue(function (value) {
  document.getElementById('display').textContent = value;
});