Precise DOM morphing
morphing
typescript
dom
Performance improvements
+28
-19
+28
-19
src/morphlex.ts
+28
-19
src/morphlex.ts
···
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+
const SupportsMoveBefore = "moveBefore" in Element.prototype
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const ParentNodeTypes = new Set([1, 9, 11])
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const DisablableElements = new Set(["input", "button", "select", "textarea", "option", "optgroup", "fieldset"])
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const ValuableElements = new Set(["input", "select", "textarea"])
···
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afterChildrenVisited?: (parent: ParentNode) => void
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}
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type NodeWithMoveBefore = ParentNode & {
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moveBefore: (node: ChildNode, before: ChildNode | null) => void
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}
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export function morph(from: ChildNode, to: ChildNode | NodeListOf<ChildNode> | string, options: Options = {}): void {
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if (typeof to === "string") to = parseString(to).childNodes
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new Morph(options).morph(from, to)
···
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function moveBefore(parent: ParentNode, node: ChildNode, insertionPoint: ChildNode | null): void {
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if (node === insertionPoint) return
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if (node.parentNode === parent && node.nextSibling === insertionPoint) return
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// Use moveBefore when available and the node is already in the same parent
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if ("moveBefore" in parent && typeof parent.moveBefore === "function" && node.parentNode === parent) {
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parent.moveBefore(node, insertionPoint)
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} else {
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parent.insertBefore(node, insertionPoint)
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if (node.parentNode === parent) {
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if (node.nextSibling === insertionPoint) return
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if (supportsMoveBefore(parent)) {
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parent.moveBefore(node, insertionPoint)
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return
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}
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}
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parent.insertBefore(node, insertionPoint)
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}
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class Morph {
···
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private morphOneToOne(from: ChildNode, to: ChildNode): void {
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// Fast path: if nodes are exactly the same object, skip morphing
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if (from.isSameNode?.(to)) return
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if (from === to) return
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if (from.isEqualNode?.(to)) return
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if (!(this.options.beforeNodeVisited?.(from, to) ?? true)) return
···
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if (!isElement(node)) continue
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const idSet = this.idMap.get(node)
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if (!idSet) continue
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const idSetArray = [...idSet]
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for (const candidate of candidates) {
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candidateLoop: for (const candidate of candidates) {
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if (isElement(candidate)) {
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const candidateIdSet = this.idMap.get(candidate)
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if (candidateIdSet && idSetArray.some((id) => candidateIdSet.has(id))) {
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matches.set(node, candidate)
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unmatched.delete(node)
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candidates.delete(candidate)
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break
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if (candidateIdSet) {
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for (const id of idSet) {
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if (candidateIdSet.has(id)) {
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matches.set(node, candidate)
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unmatched.delete(node)
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candidates.delete(candidate)
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break candidateLoop
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}
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}
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}
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}
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}
···
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if (!isElement(node)) continue
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const className = node.className
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const name = node.getAttribute("name")
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const ariaLabel = node.getAttribute("aria-label")
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const ariaDescription = node.getAttribute("aria-description")
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const href = node.getAttribute("href")
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const src = node.getAttribute("src")
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···
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node.localName === candidate.localName &&
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((className !== "" && className === candidate.className) ||
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(name !== "" && name === candidate.getAttribute("name")) ||
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(ariaLabel !== "" && ariaLabel === candidate.getAttribute("aria-label")) ||
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(ariaDescription !== "" && ariaDescription === candidate.getAttribute("aria-description")) ||
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(href !== "" && href === candidate.getAttribute("href")) ||
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(src !== "" && src === candidate.getAttribute("src")))
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) {
···
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}
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}
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}
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}
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function supportsMoveBefore(_node: ParentNode): _node is NodeWithMoveBefore {
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return SupportsMoveBefore
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}
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function isDisablableElement(element: Element): element is DisablableElement {