A reactive svg implementation, based on reactive-coffee by @yang

rxv

bind = rx.bind
ObsCell = rx.ObsCell
ObsArray = rx.ObsArray

@rxv = {}


events = ["click", "mousedown", "mouseup"]

specialAttrs = rxv.specialAttrs = {
  init: (elt, fn) -> fn.call(elt)
}

for ev in events
  do (ev) ->
    specialAttrs[ev] = (elt, fn) -> elt.addEventListener ev, fn


setProp = (elt, prop, val) ->
  elt.setAttribute prop, val

rxv.mktag = mktag = (tag) -> 
	(arg1, arg2) ->
		# arguments are either (), (attrs: Object), (contents: non-Object), or
		# (attrs: Object, contents: non-Object)
		[attrs, contents] =
			if not arg1? and not arg2?
				[{}, null]
			else if arg2?
				[arg1, arg2]
			else if _.isString(arg1) or arg1 instanceof SVGElement or _.isArray(arg1) or arg1 instanceof ObsCell or arg1 instanceof ObsArray
	    		[{}, arg1]
			else
				[arg1, null]

		elt = document.createElementNS('http://www.w3.org/2000/svg', tag)
		for name, value of _.omit(attrs, _.keys(specialAttrs))
	    	if value instanceof ObsCell
	    		do (name) -> 
	    			value.onSet.sub ([old, val]) -> setProp(elt, name, val)
	    	else
	    		setProp(elt, name, value)

		if contents?
			toNodes = (contents) ->
				for child in contents
					if _.isString(child)
						document.createTextNode(child)
					else if child instanceof SVGElement
						child
					else
						throw 'Unknown element type in array: ' + child.constructor.name

			updateContents = (contents) ->
				(elt.removeChild elt.firstChild) while elt.firstChild
				if _.isArray(contents)
					(elt.appendChild node) for node in toNodes(contents)
				else if _.isString(contents)
	  				updateContents([contents])
	  			else
	      			throw 'Unknown type for contents: ' + contents.constructor.name

			if contents instanceof ObsArray
				contents.onChange.sub ([index, removed, added]) -> 
					(elt.removeChild elt.childNodes[index]) for i in [0...removed.length]
					toAdd = toNodes(added)
					if index == elt.childNodes.length
						(elt.appendChild node) for node in toAdd
					else 
						(elt.childNodes[index].insertBefore node) for node in toAdd
					
			
			else if contents instanceof ObsCell
				contents.onSet.sub(([old, val]) -> updateContents(val))
			
			else
				updateContents(contents)

		for key of attrs when key of specialAttrs
			specialAttrs[key](elt, attrs[key], attrs, contents)
		elt

tags = ['svg', 'rect', 'text', 'g']
rxv.tags = _.object([tag, rxv.mktag(tag)] for tag in tags)
rxv.importTags = (x) => _(x ? this).extend(rxv.tags)