happy-dom/src/tree-walker/NodeIterator.ts

Happy DOM is a JavaScript implementation of a web browser without its graphical user interface. It includes many web standards from WHATWG DOM and HTML.

import INodeFilter from './INodeFilter.js';
import TreeWalker from './TreeWalker.js';
import Node from '../nodes/node/Node.js';
import * as PropertySymbol from '../PropertySymbol.js';
import NodeFilter from './NodeFilter.js';

/**
 * The NodeIterator object represents the nodes of a document subtree and a position within them.
 *
 * Reference:
 * https://developer.mozilla.org/en-US/docs/Web/API/NodeIterator
 */
export default class NodeIterator {
	#root: Node = null;
	#whatToShow = -1;
	#filter: INodeFilter = null;
	#walker: TreeWalker;
	#atRoot = true;

	/**
	 * Constructor.
	 *
	 * @param root Root.
	 * @param [whatToShow] What to show.
	 * @param [filter] Filter.
	 */
	constructor(root: Node, whatToShow = -1, filter: INodeFilter = null) {
		this.#root = root;
		this.#whatToShow = whatToShow;
		this.#filter = filter;
		this.#walker = new TreeWalker(root, whatToShow, filter);
	}

	/**
	 * Returns root.
	 *
	 * @returns Root.
	 */
	public get root(): Node | null {
		return this.#root;
	}

	/**
	 * Returns what to show.
	 *
	 * @returns What to show.
	 */
	public get whatToShow(): number {
		return this.#whatToShow;
	}

	/**
	 * Returns filter.
	 *
	 * @returns Filter.
	 */
	public get filter(): INodeFilter {
		return this.#filter;
	}

	/**
	 * Moves the current Node to the next visible node in the document order.
	 *
	 * @returns Current node.
	 */
	public nextNode(): Node {
		if (this.#atRoot) {
			this.#atRoot = false;
			if (this.#walker[PropertySymbol.filterNode](this.#root) !== NodeFilter.FILTER_ACCEPT) {
				return this.#walker.nextNode();
			}
			return this.#root;
		}
		return this.#walker.nextNode();
	}

	/**
	 * Moves the current Node to the previous visible node in the document order, and returns the found node. It also moves the current node to this one. If no such node exists, or if it is before that the root node defined at the object construction, returns null and the current node is not changed.
	 *
	 * @returns Current node.
	 */
	public previousNode(): Node {
		return this.#walker.previousNode();
	}
}