let onAttributeAddeds = []
let onElRemoveds = []
let onElAddeds = []
export function onElAdded(callback) {
onElAddeds.push(callback)
}
export function onElRemoved(el, callback) {
if (typeof callback === 'function') {
if (! el._x_cleanups) el._x_cleanups = []
el._x_cleanups.push(callback)
} else {
callback = el
onElRemoveds.push(callback)
}
}
export function onAttributesAdded(callback) {
onAttributeAddeds.push(callback)
}
export function onAttributeRemoved(el, name, callback) {
if (! el._x_attributeCleanups) el._x_attributeCleanups = {}
if (! el._x_attributeCleanups[name]) el._x_attributeCleanups[name] = []
el._x_attributeCleanups[name].push(callback)
}
export function cleanupAttributes(el, names) {
if (! el._x_attributeCleanups) return
Object.entries(el._x_attributeCleanups).forEach(([name, value]) => {
if (names === undefined || names.includes(name)) {
value.forEach(i => i())
delete el._x_attributeCleanups[name]
}
})
}
export function cleanupElement(el) {
if (el._x_cleanups) {
while (el._x_cleanups.length) el._x_cleanups.pop()()
}
}
let observer = new MutationObserver(onMutate)
let currentlyObserving = false
export function startObservingMutations() {
observer.observe(document, { subtree: true, childList: true, attributes: true, attributeOldValue: true })
currentlyObserving = true
}
export function stopObservingMutations() {
flushObserver()
observer.disconnect()
currentlyObserving = false
}
let queuedMutations = []
export function flushObserver() {
let records = observer.takeRecords()
queuedMutations.push(() => records.length > 0 && onMutate(records))
let queueLengthWhenTriggered = queuedMutations.length
queueMicrotask(() => {
// If these two lengths match, then we KNOW that this is the LAST
// flush in the current event loop. This way, we can process
// all mutations in one batch at the end of everything...
if (queuedMutations.length === queueLengthWhenTriggered) {
// Now Alpine can process all the mutations...
while (queuedMutations.length > 0) queuedMutations.shift()()
}
})
}
export function mutateDom(callback) {
if (! currentlyObserving) return callback()
stopObservingMutations()
let result = callback()
startObservingMutations()
return result
}
let isCollecting = false
let deferredMutations = []
export function deferMutations() {
isCollecting = true
}
export function flushAndStopDeferringMutations() {
isCollecting = false
onMutate(deferredMutations)
deferredMutations = []
}
function onMutate(mutations) {
if (isCollecting) {
deferredMutations = deferredMutations.concat(mutations)
return
}
let addedNodes = new Set
let removedNodes = new Set
let addedAttributes = new Map
let removedAttributes = new Map
for (let i = 0; i < mutations.length; i++) {
if (mutations[i].target._x_ignoreMutationObserver) continue
if (mutations[i].type === 'childList') {
mutations[i].addedNodes.forEach(node => node.nodeType === 1 && addedNodes.add(node))
mutations[i].removedNodes.forEach(node => node.nodeType === 1 && removedNodes.add(node))
}
if (mutations[i].type === 'attributes') {
let el = mutations[i].target
let name = mutations[i].attributeName
let oldValue = mutations[i].oldValue
let add = () => {
if (! addedAttributes.has(el)) addedAttributes.set(el, [])
addedAttributes.get(el).push({ name, value: el.getAttribute(name) })
}
let remove = () => {
if (! removedAttributes.has(el)) removedAttributes.set(el, [])
removedAttributes.get(el).push(name)
}
// New attribute.
if (el.hasAttribute(name) && oldValue === null) {
add()
// Changed attribute.
} else if (el.hasAttribute(name)) {
remove()
add()
// Removed attribute.
} else {
remove()
}
}
}
removedAttributes.forEach((attrs, el) => {
cleanupAttributes(el, attrs)
})
addedAttributes.forEach((attrs, el) => {
onAttributeAddeds.forEach(i => i(el, attrs))
})
for (let node of removedNodes) {
// If an element gets moved on a page, it's registered
// as both an "add" and "remove", so we want to skip those.
if (addedNodes.has(node)) continue
onElRemoveds.forEach(i => i(node))
}
// Mutations are bundled together by the browser but sometimes
// for complex cases, there may be javascript code adding a wrapper
// and then an alpine component as a child of that wrapper in the same
// function and the mutation observer will receive 2 different mutations.
// when it comes time to run them, the dom contains both changes so the child
// element would be processed twice as Alpine calls initTree on
// both mutations. We mark all nodes as _x_ignored and only remove the flag
// when processing the node to avoid those duplicates.
addedNodes.forEach((node) => {
node._x_ignoreSelf = true
node._x_ignore = true
})
for (let node of addedNodes) {
// If the node was eventually removed as part of one of his
// parent mutations, skip it
if (removedNodes.has(node)) continue
if (! node.isConnected) continue
delete node._x_ignoreSelf
delete node._x_ignore
onElAddeds.forEach(i => i(node))
node._x_ignore = true
node._x_ignoreSelf = true
}
addedNodes.forEach((node) => {
delete node._x_ignoreSelf
delete node._x_ignore
})
addedNodes = null
removedNodes = null
addedAttributes = null
removedAttributes = null
}