/
selector_observer.coffee
73 lines (62 loc) · 2.25 KB
/
selector_observer.coffee
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class SelectorProcessor
constructor: ->
@selectors = {}
add: (selector, callback) ->
@selectors[selector] ?= []
@selectors[selector].push(callback)
processElements: (elements) =>
executions = new Map()
elements.forEach (e) =>
@processElement(e, executions)
executions.forEach (elements, callback) ->
callback(elements)
processElement: (element, executions) =>
for selector, callbacks of @selectors
for matchingElement in @findMatchingElements(element, selector)
for callback in callbacks
selectorArr = executions.get(callback)
if selectorArr && selectorArr.length
selectorArr.push(matchingElement)
else
executions.set(callback, [matchingElement])
findMatchingElements: (element, selector) ->
elements = []
elements.push(element) if matches(element, selector)
elements.concat(element.querySelectorAll(selector)...)
matches = do ->
element = document.documentElement
method = element.matches ?
element.matchesSelector ?
element.webkitMatchesSelector ?
element.mozMatchesSelector ?
element.msMatchesSelector
(element, selector) ->
method.call(element, selector)
class @SelectorObserver
constructor: ->
@addProcessor = new SelectorProcessor()
@removeProcessor = new SelectorProcessor()
@observer = new MutationObserver @processMutations
$ =>
setTimeout (=>
@observer.observe document, childList: true, subtree: true
@processBody()
), 1
add: (selector, callback) ->
@addProcessor.add(selector, callback)
remove: (selector, callback) ->
@removeProcessor.add(selector, callback)
processBody: () ->
@addProcessor.processElements([document.body])
processMutations: (mutations) =>
addedElements = new Set
removedElements = new Set
for mutation in mutations
switch mutation.type
when "childList"
for node in mutation.addedNodes when node.nodeType is Node.ELEMENT_NODE
addedElements.add(node)
for node in mutation.removedNodes when node.nodeType is Node.ELEMENT_NODE
removedElements.add(node)
@removeProcessor.processElements(removedElements)
@addProcessor.processElements(addedElements)