raimohanska/bacon.js — pull request #25 by lautis (2012-10-21 21:02:02+00:00)
Title: Allow null and undefined to be initial value of a property

Currently, `null` and `undefined` are not emitted as initial values of a property.

For example,

```coffee script

bus = new Bacon.Bus
bus.toProperty(null).onValue((a) -> console.log a)
# no initial value received, unexpected
bus.push undefined
# callback is triggered, a == undefined as expected
```

The PR makes initial value argument of EventStream::scan optional. A new special value `Bacon.none` is added to differentiate `null` and `undefined` from no initial value.