Compare stream style

gistfile1.js

$(function() {

  var spaceKeyCode = 32;

  //-----------------------------------------

  var stream = require('dim')();
  var model = {};

  stream
    .setDep('user', model, '*^')
    .setDep('error', 'errorName1')
    .on('keyup', document)
    .on('keydown', document)
    .pipe(setKeyCode, [null, 'streamName'])
    .filter(isSpaceKey, 'keyCode')
    .pipe(changeText, ['streamName', 'user^getName', 'next'])
    .error()
    .user();

  function isSpaceKey(keyCode) {
    return keyCode === spaceKeyCode;
  }

  function setKeyCode(event) {
    this.setDep('keyCode', event.keyCode);
    return true;
  }

  function changeText(streamName, getName, next) {
    $('#keyState').text(streamName === 'keydown');
    $('#name').text(getName());
    getName(function(name) {
      $('#name').text(name);
      next(null, name);
    });
  }

  //-----------------------------------------

  var spaceDown = false;

  function updateResult(result) {
    $('#keyState').text(spaceDown);
  }

  $(document).on('keyup', function(event) {
    var keyCode = event.keyCode;
    if (keyCode === spaceKeyCode) {
      spaceDown = false;
      updateResult(spaceDown);
    }
  });

  $(document).on('keydown', function(event) {
    var keyCode = event.keyCode;
    if (keyCode === spaceKeyCode) {
      spaceDown = true;
      updateResult(spaceDown);
    }
  });

});



$(function() {
  // allKeyUps :: Observable KeyEvent
  var allKeyUps = $(document).asEventStream("keyup")
  var allKeyDowns = $(document).asEventStream("keydown")

  // always :: a -> (b -> a)
  function always(value) {
      return function(_) {
        return value
      }
    }
    // keyCodeIs :: Int -> (KeyEvent -> Bool)
  function keyCodeIs(keyCode) {
      return function(event) {
        return event.keyCode == keyCode
      }
    }
    // keyUps :: Int -> Observable KeyEvent
  function keyUps(keyCode) {
    return allKeyUps.filter(keyCodeIs(keyCode))
  }

  function keyDowns(keyCode) {
    return allKeyDowns.filter(keyCodeIs(keyCode))
  }

  // keyState :: Int -> Observable Bool
  function keyState(keyCode) {
    return keyDowns(keyCode).map(always(true))
      .merge(keyUps(keyCode).map(always(false)))
      .toProperty(false)
  }

  keyState(32).onValue(function(spaceDown) {
    $('#keyState').text(spaceDown)
  })
})