redux style reducer with vdom, baconjs and immutablejs

vdom-stream.js

import Immutable from 'immutable'
import Bacon from 'baconjs'
import h from 'virtual-dom/h'
import diff from 'virtual-dom/diff'
import patch from 'virtual-dom/patch'
import createElement from 'virtual-dom/create-element'


const INCREMENT = 'INCREMENT'
const DECREMENT = 'DECREMENT'


// State, Action -> State
function reducer (state = initialState, action) {

	switch (action.type) {

	case INCREMENT:
		return state.set('count', state.get('count') + 1)

	case DECREMENT:
		return state.set('count', state.get('count') - 1)

	default:
		return state
	}
}

// State -> VDom
function view (state) {

	return h('div', {},
				[ h('b', { onclick: () => actions.push({ type: DECREMENT }) }, ['[-]'])
				, String(state.get('count'))
				, h('b', { onclick: () => actions.push({ type: INCREMENT }) }, ['[+]']) 
				])
}

// State
const initialState = Immutable.fromJS({
	count: 0
})

// VDom
const initialVDom = view(initialState)

// Bus Action
const actions = new Bacon.Bus() // like elm mailbox

// Stream State
const model = actions.scan(initialState, reducer) // scan is like elm foldp

// Stream VDom
const vDoms = model.map(view)

// Stream Patch
const patches = vDoms.scan(initialVDom, diff)


// DomNode, VDom, Stream Patch -> _
function mount (parent, vDom, patchesStream) {

	var dom = createElement(vDom)

	patchesStream.onValue(patches => {
		dom = patch(dom, patches)
	})

	parent.appendChild(dom)
}

mount(document.body, initialVDom, patches)