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https://github.com/fastmail/Squire.git
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116 lines
3.2 KiB
TypeScript
116 lines
3.2 KiB
TypeScript
type NODE_TYPE = 1 | 4 | 5;
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const SHOW_ELEMENT = 1; // NodeFilter.SHOW_ELEMENT;
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const SHOW_TEXT = 4; // NodeFilter.SHOW_TEXT;
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const SHOW_ELEMENT_OR_TEXT = 5; // SHOW_ELEMENT|SHOW_TEXT;
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const always = (): true => true;
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class TreeIterator<T extends Node> {
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root: Node;
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currentNode: Node;
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nodeType: NODE_TYPE;
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filter: (n: T) => boolean;
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constructor(root: Node, nodeType: NODE_TYPE, filter?: (n: T) => boolean) {
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this.root = root;
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this.currentNode = root;
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this.nodeType = nodeType;
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this.filter = filter || always;
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}
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isAcceptableNode(node: Node): boolean {
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const nodeType = node.nodeType;
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const nodeFilterType =
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nodeType === Node.ELEMENT_NODE
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? SHOW_ELEMENT
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: nodeType === Node.TEXT_NODE
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? SHOW_TEXT
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: 0;
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return !!(nodeFilterType & this.nodeType) && this.filter(node as T);
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}
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nextNode(): T | null {
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const root = this.root;
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let current: Node | null = this.currentNode;
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let node: Node | null;
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while (true) {
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node = current.firstChild;
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while (!node && current) {
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if (current === root) {
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break;
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}
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node = current.nextSibling;
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if (!node) {
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current = current.parentNode;
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}
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}
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if (!node) {
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return null;
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}
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if (this.isAcceptableNode(node)) {
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this.currentNode = node;
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return node as T;
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}
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current = node;
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}
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}
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previousNode(): T | null {
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const root = this.root;
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let current: Node | null = this.currentNode;
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let node: Node | null;
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while (true) {
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if (current === root) {
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return null;
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}
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node = current.previousSibling;
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if (node) {
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while ((current = node.lastChild)) {
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node = current;
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}
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} else {
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node = current.parentNode;
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}
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if (!node) {
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return null;
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}
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if (this.isAcceptableNode(node)) {
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this.currentNode = node;
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return node as T;
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}
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current = node;
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}
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}
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// Previous node in post-order.
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previousPONode(): T | null {
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const root = this.root;
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let current: Node | null = this.currentNode;
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let node: Node | null;
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while (true) {
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node = current.lastChild;
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while (!node && current) {
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if (current === root) {
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break;
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}
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node = current.previousSibling;
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if (!node) {
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current = current.parentNode;
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}
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}
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if (!node) {
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return null;
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}
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if (this.isAcceptableNode(node)) {
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this.currentNode = node;
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return node as T;
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}
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current = node;
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}
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}
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}
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// ---
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export { TreeIterator, SHOW_ELEMENT, SHOW_TEXT, SHOW_ELEMENT_OR_TEXT };
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