@xmldom/xmldom/lib/dom.js

A pure JavaScript W3C standard-based (XML DOM Level 2 Core) DOMParser and XMLSerializer module.

'use strict';

var conventions = require('./conventions');
var find = conventions.find;
var hasDefaultHTMLNamespace = conventions.hasDefaultHTMLNamespace;
var hasOwn = conventions.hasOwn;
var isHTMLMimeType = conventions.isHTMLMimeType;
var isHTMLRawTextElement = conventions.isHTMLRawTextElement;
var isHTMLVoidElement = conventions.isHTMLVoidElement;
var MIME_TYPE = conventions.MIME_TYPE;
var NAMESPACE = conventions.NAMESPACE;

/**
 * Private DOM Constructor symbol
 *
 * Internal symbol used for construction of all classes whose constructors should be private.
 * Currently used for checks in `Node`, `Document`, `Element`, `Attr`, `CharacterData`, `Text`, `Comment`,
 * `CDATASection`, `DocumentType`, `Notation`, `Entity`, `EntityReference`, `DocumentFragment`, `ProcessingInstruction`
 * so the constructor can't be used from outside the module.
 */
var PDC = Symbol();

var errors = require('./errors');
var DOMException = errors.DOMException;
var DOMExceptionName = errors.DOMExceptionName;

var g = require('./grammar');

/**
 * Checks if the given symbol equals the Private DOM Constructor symbol (PDC)
 * and throws an Illegal constructor exception when the symbols don't match.
 * This ensures that the constructor remains private and can't be used outside this module.
 */
function checkSymbol(symbol) {
	if (symbol !== PDC) {
		throw new TypeError('Illegal constructor');
	}
}

/**
 * A prerequisite for `[].filter`, to drop elements that are empty.
 *
 * @param {string} input
 * The string to be checked.
 * @returns {boolean}
 * Returns `true` if the input string is not empty, `false` otherwise.
 */
function notEmptyString(input) {
	return input !== '';
}
/**
 * Splits a string on ASCII whitespace characters (U+0009 TAB, U+000A LF, U+000C FF, U+000D CR,
 * U+0020 SPACE).
 * It follows the definition from the infra specification from WHATWG.
 *
 * @param {string} input
 * The string to be split.
 * @returns {string[]}
 * An array of the split strings. The array can be empty if the input string is empty or only
 * contains whitespace characters.
 * @see {@link https://infra.spec.whatwg.org/#split-on-ascii-whitespace}
 * @see {@link https://infra.spec.whatwg.org/#ascii-whitespace}
 */
function splitOnASCIIWhitespace(input) {
	// U+0009 TAB, U+000A LF, U+000C FF, U+000D CR, U+0020 SPACE
	return input ? input.split(/[\t\n\f\r ]+/).filter(notEmptyString) : [];
}

/**
 * Adds element as a key to current if it is not already present.
 *
 * @param {Record<string, boolean | undefined>} current
 * The current record object to which the element will be added as a key.
 * The object's keys are string types and values are either boolean or undefined.
 * @param {string} element
 * The string to be added as a key to the current record.
 * @returns {Record<string, boolean | undefined>}
 * The updated record object after the addition of the new element.
 */
function orderedSetReducer(current, element) {
	if (!hasOwn(current, element)) {
		current[element] = true;
	}
	return current;
}

/**
 * Converts a string into an ordered set by splitting the input on ASCII whitespace and
 * ensuring uniqueness of elements.
 * This follows the definition of an ordered set from the infra specification by WHATWG.
 *
 * @param {string} input
 * The input string to be transformed into an ordered set.
 * @returns {string[]}
 * An array of unique strings obtained from the input, preserving the original order.
 * The array can be empty if the input string is empty or only contains whitespace characters.
 * @see {@link https://infra.spec.whatwg.org/#ordered-set}
 */
function toOrderedSet(input) {
	if (!input) return [];
	var list = splitOnASCIIWhitespace(input);
	return Object.keys(list.reduce(orderedSetReducer, {}));
}

/**
 * Uses `list.indexOf` to implement a function that behaves like `Array.prototype.includes`.
 * This function is used in environments where `Array.prototype.includes` may not be available.
 *
 * @param {any[]} list
 * The array in which to search for the element.
 * @returns {function(any): boolean}
 * A function that accepts an element and returns a boolean indicating whether the element is
 * included in the provided list.
 */
function arrayIncludes(list) {
	return function (element) {
		return list && list.indexOf(element) !== -1;
	};
}

/**
 * Validates a qualified name based on the criteria provided in the DOM specification by
 * WHATWG.
 *
 * @param {string} qualifiedName
 * The qualified name to be validated.
 * @throws {DOMException}
 * With code {@link DOMException.INVALID_CHARACTER_ERR} if the qualified name contains an
 * invalid character.
 * @see {@link https://dom.spec.whatwg.org/#validate}
 */
function validateQualifiedName(qualifiedName) {
	if (!g.QName_exact.test(qualifiedName)) {
		throw new DOMException(DOMException.INVALID_CHARACTER_ERR, 'invalid character in qualified name "' + qualifiedName + '"');
	}
}

/**
 * Validates a qualified name and the namespace associated with it,
 * based on the criteria provided in the DOM specification by WHATWG.
 *
 * @param {string | null} namespace
 * The namespace to be validated. It can be a string or null.
 * @param {string} qualifiedName
 * The qualified name to be validated.
 * @returns {[namespace: string | null, prefix: string | null, localName: string]}
 * Returns a tuple with the namespace,
 * prefix and local name of the qualified name.
 * @throws {DOMException}
 * Throws a DOMException if the qualified name or the namespace is not valid.
 * @see {@link https://dom.spec.whatwg.org/#validate-and-extract}
 */
function validateAndExtract(namespace, qualifiedName) {
	validateQualifiedName(qualifiedName);
	namespace = namespace || null;
	/**
	 * @type {string | null}
	 */
	var prefix = null;
	var localName = qualifiedName;
	if (qualifiedName.indexOf(':') >= 0) {
		var splitResult = qualifiedName.split(':');
		prefix = splitResult[0];
		localName = splitResult[1];
	}
	if (prefix !== null && namespace === null) {
		throw new DOMException(DOMException.NAMESPACE_ERR, 'prefix is non-null and namespace is null');
	}
	if (prefix === 'xml' && namespace !== conventions.NAMESPACE.XML) {
		throw new DOMException(DOMException.NAMESPACE_ERR, 'prefix is "xml" and namespace is not the XML namespace');
	}
	if ((prefix === 'xmlns' || qualifiedName === 'xmlns') && namespace !== conventions.NAMESPACE.XMLNS) {
		throw new DOMException(
			DOMException.NAMESPACE_ERR,
			'either qualifiedName or prefix is "xmlns" and namespace is not the XMLNS namespace'
		);
	}
	if (namespace === conventions.NAMESPACE.XMLNS && prefix !== 'xmlns' && qualifiedName !== 'xmlns') {
		throw new DOMException(
			DOMException.NAMESPACE_ERR,
			'namespace is the XMLNS namespace and neither qualifiedName nor prefix is "xmlns"'
		);
	}
	return [namespace, prefix, localName];
}

/**
 * Copies properties from one object to another.
 * It only copies the object's own (not inherited) properties.
 *
 * @param {Object} src
 * The source object from which properties are copied.
 * @param {Object} dest
 * The destination object to which properties are copied.
 */
function copy(src, dest) {
	for (var p in src) {
		if (hasOwn(src, p)) {
			dest[p] = src[p];
		}
	}
}

/**
 * Extends a class with the properties and methods of a super class.
 * It uses a form of prototypal inheritance, and establishes the `constructor` property
 * correctly(?).
 *
 * It is not clear to the current maintainers if this implementation is making sense,
 * since it creates an intermediate prototype function,
 * which all properties of `Super` are copied onto using `_copy`.
 *
 * @param {Object} Class
 * The class that is to be extended.
 * @param {Object} Super
 * The super class from which properties and methods are inherited.
 * @private
 */
function _extends(Class, Super) {
	var pt = Class.prototype;
	if (!(pt instanceof Super)) {
		function t() {}
		t.prototype = Super.prototype;
		t = new t();
		copy(pt, t);
		Class.prototype = pt = t;
	}
	if (pt.constructor != Class) {
		if (typeof Class != 'function') {
			console.error('unknown Class:' + Class);
		}
		pt.constructor = Class;
	}
}

var NodeType = {};
var ELEMENT_NODE = (NodeType.ELEMENT_NODE = 1);
var ATTRIBUTE_NODE = (NodeType.ATTRIBUTE_NODE = 2);
var TEXT_NODE = (NodeType.TEXT_NODE = 3);
var CDATA_SECTION_NODE = (NodeType.CDATA_SECTION_NODE = 4);
var ENTITY_REFERENCE_NODE = (NodeType.ENTITY_REFERENCE_NODE = 5);
var ENTITY_NODE = (NodeType.ENTITY_NODE = 6);
var PROCESSING_INSTRUCTION_NODE = (NodeType.PROCESSING_INSTRUCTION_NODE = 7);
var COMMENT_NODE = (NodeType.COMMENT_NODE = 8);
var DOCUMENT_NODE = (NodeType.DOCUMENT_NODE = 9);
var DOCUMENT_TYPE_NODE = (NodeType.DOCUMENT_TYPE_NODE = 10);
var DOCUMENT_FRAGMENT_NODE = (NodeType.DOCUMENT_FRAGMENT_NODE = 11);
var NOTATION_NODE = (NodeType.NOTATION_NODE = 12);

var DocumentPosition = conventions.freeze({
	DOCUMENT_POSITION_DISCONNECTED: 1,
	DOCUMENT_POSITION_PRECEDING: 2,
	DOCUMENT_POSITION_FOLLOWING: 4,
	DOCUMENT_POSITION_CONTAINS: 8,
	DOCUMENT_POSITION_CONTAINED_BY: 16,
	DOCUMENT_POSITION_IMPLEMENTATION_SPECIFIC: 32,
});

//helper functions for compareDocumentPosition
/**
 * Finds the common ancestor in two parent chains.
 *
 * @param {Node[]} a
 * The first parent chain.
 * @param {Node[]} b
 * The second parent chain.
 * @returns {Node}
 * The common ancestor node if it exists. If there is no common ancestor, the function will
 * return `null`.
 */
function commonAncestor(a, b) {
	if (b.length < a.length) return commonAncestor(b, a);
	var c = null;
	for (var n in a) {
		if (a[n] !== b[n]) return c;
		c = a[n];
	}
	return c;
}

/**
 * Assigns a unique identifier to a document to ensure consistency while comparing unrelated
 * nodes.
 *
 * @param {Document} doc
 * The document to which a unique identifier is to be assigned.
 * @returns {string}
 * The unique identifier of the document. If the document already had a unique identifier, the
 * function will return the existing one.
 */
function docGUID(doc) {
	if (!doc.guid) doc.guid = Math.random();
	return doc.guid;
}
//-- end of helper functions

/**
 * The NodeList interface provides the abstraction of an ordered collection of nodes,
 * without defining or constraining how this collection is implemented.
 * NodeList objects in the DOM are live.
 * The items in the NodeList are accessible via an integral index, starting from 0.
 * You can also access the items of the NodeList with a `for...of` loop.
 *
 * @class NodeList
 * @see http://www.w3.org/TR/2000/REC-DOM-Level-2-Core-20001113/core.html#ID-536297177
 * @constructs NodeList
 */
function NodeList() {}
NodeList.prototype = {
	/**
	 * The number of nodes in the list. The range of valid child node indices is 0 to length-1
	 * inclusive.
	 *
	 * @type {number}
	 */
	length: 0,
	/**
	 * Returns the item at `index`. If index is greater than or equal to the number of nodes in
	 * the list, this returns null.
	 *
	 * @param index
	 * Unsigned long Index into the collection.
	 * @returns {Node | null}
	 * The node at position `index` in the NodeList,
	 * or null if that is not a valid index.
	 */
	item: function (index) {
		return index >= 0 && index < this.length ? this[index] : null;
	},
	/**
	 * Returns a string representation of the NodeList.
	 *
	 * Accepts the same `options` object as `XMLSerializer.prototype.serializeToString`
	 * (`requireWellFormed`, `splitCDATASections`, `nodeFilter`). Passing a function is treated as
	 * a legacy `nodeFilter` for backward compatibility.
	 *
	 * @param {Object | function} [options]
	 * @param {boolean} [options.requireWellFormed=false]
	 * @param {boolean} [options.splitCDATASections=true]
	 * @param {function} [options.nodeFilter]
	 * @returns {string}
	 */
	toString: function (options) {
		var opts;
		if (typeof options === 'function') {
			opts = { requireWellFormed: false, splitCDATASections: true, nodeFilter: options };
		} else if (!!options) {
			opts = {
				requireWellFormed: !!options.requireWellFormed,
				splitCDATASections: options.splitCDATASections !== false,
				nodeFilter: options.nodeFilter || null,
			};
		} else {
			opts = { requireWellFormed: false, splitCDATASections: true, nodeFilter: null };
		}
		for (var buf = [], i = 0; i < this.length; i++) {
			serializeToString(this[i], buf, null, opts);
		}
		return buf.join('');
	},
	/**
	 * Filters the NodeList based on a predicate.
	 *
	 * @param {function(Node): boolean} predicate
	 * - A predicate function to filter the NodeList.
	 * @returns {Node[]}
	 * An array of nodes that satisfy the predicate.
	 * @private
	 */
	filter: function (predicate) {
		return Array.prototype.filter.call(this, predicate);
	},
	/**
	 * Returns the first index at which a given node can be found in the NodeList, or -1 if it is
	 * not present.
	 *
	 * @param {Node} item
	 * - The Node item to locate in the NodeList.
	 * @returns {number}
	 * The first index of the node in the NodeList; -1 if not found.
	 * @private
	 */
	indexOf: function (item) {
		return Array.prototype.indexOf.call(this, item);
	},
};
NodeList.prototype[Symbol.iterator] = function () {
	var me = this;
	var index = 0;

	return {
		next: function () {
			if (index < me.length) {
				return {
					value: me[index++],
					done: false,
				};
			} else {
				return {
					done: true,
				};
			}
		},
		return: function () {
			return {
				done: true,
			};
		},
	};
};

/**
 * Represents a live collection of nodes that is automatically updated when its associated
 * document changes.
 *
 * @class LiveNodeList
 * @param {Node} node
 * The associated node.
 * @param {function} refresh
 * The function to refresh the live node list.
 * @augments NodeList
 * @constructs LiveNodeList
 */
function LiveNodeList(node, refresh) {
	this._node = node;
	this._refresh = refresh;
	_updateLiveList(this);
}
/**
 * Updates the live node list.
 *
 * @param {LiveNodeList} list
 * The live node list to update.
 * @private
 */
function _updateLiveList(list) {
	var inc = list._node._inc || list._node.ownerDocument._inc;
	if (list._inc !== inc) {
		var ls = list._refresh(list._node);
		__set__(list, 'length', ls.length);
		if (!list.$$length || ls.length < list.$$length) {
			for (var i = ls.length; i in list; i++) {
				if (hasOwn(list, i)) {
					delete list[i];
				}
			}
		}
		copy(ls, list);
		list._inc = inc;
	}
}
/**
 * Returns the node at position `index` in the LiveNodeList, or null if that is not a valid
 * index.
 *
 * @param {number} i
 * Index into the collection.
 * @returns {Node | null}
 * The node at position `index` in the LiveNodeList, or null if that is not a valid index.
 */
LiveNodeList.prototype.item = function (i) {
	_updateLiveList(this);
	return this[i] || null;
};

_extends(LiveNodeList, NodeList);

/**
 * Objects implementing the NamedNodeMap interface are used to represent collections of nodes
 * that can be accessed by name.
 * Note that NamedNodeMap does not inherit from NodeList;
 * NamedNodeMaps are not maintained in any particular order.
 * Objects contained in an object implementing NamedNodeMap may also be accessed by an ordinal
 * index,
 * but this is simply to allow convenient enumeration of the contents of a NamedNodeMap,
 * and does not imply that the DOM specifies an order to these Nodes.
 * NamedNodeMap objects in the DOM are live.
 * used for attributes or DocumentType entities
 *
 * This implementation only supports property indices, but does not support named properties,
 * as specified in the living standard.
 *
 * @class NamedNodeMap
 * @see https://dom.spec.whatwg.org/#interface-namednodemap
 * @see https://webidl.spec.whatwg.org/#dfn-supported-property-names
 * @constructs NamedNodeMap
 */
function NamedNodeMap() {}
/**
 * Returns the index of a node within the list.
 *
 * @param {Array} list
 * The list of nodes.
 * @param {Node} node
 * The node to find.
 * @returns {number}
 * The index of the node within the list, or -1 if not found.
 * @private
 */
function _findNodeIndex(list, node) {
	var i = 0;
	while (i < list.length) {
		if (list[i] === node) {
			return i;
		}
		i++;
	}
}
/**
 * Adds a new attribute to the list and updates the owner element of the attribute.
 *
 * @param {Element} el
 * The element which will become the owner of the new attribute.
 * @param {NamedNodeMap} list
 * The list to which the new attribute will be added.
 * @param {Attr} newAttr
 * The new attribute to be added.
 * @param {Attr} oldAttr
 * The old attribute to be replaced, or null if no attribute is to be replaced.
 * @returns {void}
 * @private
 */
function _addNamedNode(el, list, newAttr, oldAttr) {
	if (oldAttr) {
		list[_findNodeIndex(list, oldAttr)] = newAttr;
	} else {
		list[list.length] = newAttr;
		list.length++;
	}
	if (el) {
		newAttr.ownerElement = el;
		var doc = el.ownerDocument;
		if (doc) {
			oldAttr && _onRemoveAttribute(doc, el, oldAttr);
			_onAddAttribute(doc, el, newAttr);
		}
	}
}
/**
 * Removes an attribute from the list and updates the owner element of the attribute.
 *
 * @param {Element} el
 * The element which is the current owner of the attribute.
 * @param {NamedNodeMap} list
 * The list from which the attribute will be removed.
 * @param {Attr} attr
 * The attribute to be removed.
 * @returns {void}
 * @private
 */
function _removeNamedNode(el, list, attr) {
	//console.log('remove attr:'+attr)
	var i = _findNodeIndex(list, attr);
	if (i >= 0) {
		var lastIndex = list.length - 1;
		while (i <= lastIndex) {
			list[i] = list[++i];
		}
		list.length = lastIndex;
		if (el) {
			var doc = el.ownerDocument;
			if (doc) {
				_onRemoveAttribute(doc, el, attr);
			}
			attr.ownerElement = null;
		}
	}
}
NamedNodeMap.prototype = {
	length: 0,
	item: NodeList.prototype.item,

	/**
	 * Get an attribute by name. Note: Name is in lower case in case of HTML namespace and
	 * document.
	 *
	 * @param {string} localName
	 * The local name of the attribute.
	 * @returns {Attr | null}
	 * The attribute with the given local name, or null if no such attribute exists.
	 * @see https://dom.spec.whatwg.org/#concept-element-attributes-get-by-name
	 */
	getNamedItem: function (localName) {
		if (this._ownerElement && this._ownerElement._isInHTMLDocumentAndNamespace()) {
			localName = localName.toLowerCase();
		}
		var i = 0;
		while (i < this.length) {
			var attr = this[i];
			if (attr.nodeName === localName) {
				return attr;
			}
			i++;
		}
		return null;
	},

	/**
	 * Set an attribute.
	 *
	 * @param {Attr} attr
	 * The attribute to set.
	 * @returns {Attr | null}
	 * The old attribute with the same local name and namespace URI as the new one, or null if no
	 * such attribute exists.
	 * @throws {DOMException}
	 * With code:
	 * - {@link INUSE_ATTRIBUTE_ERR} - If the attribute is already an attribute of another
	 * element.
	 * @see https://dom.spec.whatwg.org/#concept-element-attributes-set
	 */
	setNamedItem: function (attr) {
		var el = attr.ownerElement;
		if (el && el !== this._ownerElement) {
			throw new DOMException(DOMException.INUSE_ATTRIBUTE_ERR);
		}
		var oldAttr = this.getNamedItemNS(attr.namespaceURI, attr.localName);
		if (oldAttr === attr) {
			return attr;
		}
		_addNamedNode(this._ownerElement, this, attr, oldAttr);
		return oldAttr;
	},

	/**
	 * Set an attribute, replacing an existing attribute with the same local name and namespace
	 * URI if one exists.
	 *
	 * @param {Attr} attr
	 * The attribute to set.
	 * @returns {Attr | null}
	 * The old attribute with the same local name and namespace URI as the new one, or null if no
	 * such attribute exists.
	 * @throws {DOMException}
	 * Throws a DOMException with the name "InUseAttributeError" if the attribute is already an
	 * attribute of another element.
	 * @see https://dom.spec.whatwg.org/#concept-element-attributes-set
	 */
	setNamedItemNS: function (attr) {
		return this.setNamedItem(attr);
	},

	/**
	 * Removes an attribute specified by the local name.
	 *
	 * @param {string} localName
	 * The local name of the attribute to be removed.
	 * @returns {Attr}
	 * The attribute node that was removed.
	 * @throws {DOMException}
	 * With code:
	 * - {@link DOMException.NOT_FOUND_ERR} if no attribute with the given name is found.
	 * @see https://dom.spec.whatwg.org/#dom-namednodemap-removenameditem
	 * @see https://dom.spec.whatwg.org/#concept-element-attributes-remove-by-name
	 */
	removeNamedItem: function (localName) {
		var attr = this.getNamedItem(localName);
		if (!attr) {
			throw new DOMException(DOMException.NOT_FOUND_ERR, localName);
		}
		_removeNamedNode(this._ownerElement, this, attr);
		return attr;
	},

	/**
	 * Removes an attribute specified by the namespace and local name.
	 *
	 * @param {string | null} namespaceURI
	 * The namespace URI of the attribute to be removed.
	 * @param {string} localName
	 * The local name of the attribute to be removed.
	 * @returns {Attr}
	 * The attribute node that was removed.
	 * @throws {DOMException}
	 * With code:
	 * - {@link DOMException.NOT_FOUND_ERR} if no attribute with the given namespace URI and local
	 * name is found.
	 * @see https://dom.spec.whatwg.org/#dom-namednodemap-removenameditemns
	 * @see https://dom.spec.whatwg.org/#concept-element-attributes-remove-by-namespace
	 */
	removeNamedItemNS: function (namespaceURI, localName) {
		var attr = this.getNamedItemNS(namespaceURI, localName);
		if (!attr) {
			throw new DOMException(DOMException.NOT_FOUND_ERR, namespaceURI ? namespaceURI + ' : ' + localName : localName);
		}
		_removeNamedNode(this._ownerElement, this, attr);
		return attr;
	},

	/**
	 * Get an attribute by namespace and local name.
	 *
	 * @param {string | null} namespaceURI
	 * The namespace URI of the attribute.
	 * @param {string} localName
	 * The local name of the attribute.
	 * @returns {Attr | null}
	 * The attribute with the given namespace URI and local name, or null if no such attribute
	 * exists.
	 * @see https://dom.spec.whatwg.org/#concept-element-attributes-get-by-namespace
	 */
	getNamedItemNS: function (namespaceURI, localName) {
		if (!namespaceURI) {
			namespaceURI = null;
		}
		var i = 0;
		while (i < this.length) {
			var node = this[i];
			if (node.localName === localName && node.namespaceURI === namespaceURI) {
				return node;
			}
			i++;
		}
		return null;
	},
};
NamedNodeMap.prototype[Symbol.iterator] = function () {
	var me = this;
	var index = 0;

	return {
		next: function () {
			if (index < me.length) {
				return {
					value: me[index++],
					done: false,
				};
			} else {
				return {
					done: true,
				};
			}
		},
		return: function () {
			return {
				done: true,
			};
		},
	};
};

/**
 * The DOMImplementation interface provides a number of methods for performing operations that
 * are independent of any particular instance of the document object model.
 *
 * The DOMImplementation interface represents an object providing methods which are not
 * dependent on any particular document.
 * Such an object is returned by the `Document.implementation` property.
 *
 * **The individual methods describe the differences compared to the specs**.
 *
 * @class DOMImplementation
 * @see https://developer.mozilla.org/en-US/docs/Web/API/DOMImplementation MDN
 * @see https://www.w3.org/TR/REC-DOM-Level-1/level-one-core.html#ID-102161490 DOM Level 1 Core
 *      (Initial)
 * @see https://www.w3.org/TR/DOM-Level-2-Core/core.html#ID-102161490 DOM Level 2 Core
 * @see https://www.w3.org/TR/DOM-Level-3-Core/core.html#ID-102161490 DOM Level 3 Core
 * @see https://dom.spec.whatwg.org/#domimplementation DOM Living Standard
 * @constructs DOMImplementation
 */
function DOMImplementation() {}

DOMImplementation.prototype = {
	/**
	 * Test if the DOM implementation implements a specific feature and version, as specified in
	 * {@link https://www.w3.org/TR/DOM-Level-3-Core/core.html#DOMFeatures DOM Features}.
	 *
	 * The DOMImplementation.hasFeature() method returns a Boolean flag indicating if a given
	 * feature is supported. The different implementations fairly diverged in what kind of
	 * features were reported. The latest version of the spec settled to force this method to
	 * always return true, where the functionality was accurate and in use.
	 *
	 * @deprecated
	 * It is deprecated and modern browsers return true in all cases.
	 * @function DOMImplementation#hasFeature
	 * @param {string} feature
	 * The name of the feature to test.
	 * @param {string} [version]
	 * This is the version number of the feature to test.
	 * @returns {boolean}
	 * Always returns true.
	 * @see https://developer.mozilla.org/en-US/docs/Web/API/DOMImplementation/hasFeature MDN
	 * @see https://www.w3.org/TR/REC-DOM-Level-1/level-one-core.html#ID-5CED94D7 DOM Level 1 Core
	 * @see https://dom.spec.whatwg.org/#dom-domimplementation-hasfeature DOM Living Standard
	 * @see https://www.w3.org/TR/DOM-Level-3-Core/core.html#ID-5CED94D7 DOM Level 3 Core
	 */
	hasFeature: function (feature, version) {
		return true;
	},
	/**
	 * Creates a DOM Document object of the specified type with its document element. Note that
	 * based on the {@link DocumentType}
	 * given to create the document, the implementation may instantiate specialized
	 * {@link Document} objects that support additional features than the "Core", such as "HTML"
	 * {@link https://www.w3.org/TR/DOM-Level-3-Core/references.html#DOM2HTML DOM Level 2 HTML}.
	 * On the other hand, setting the {@link DocumentType} after the document was created makes
	 * this very unlikely to happen. Alternatively, specialized {@link Document} creation methods,
	 * such as createHTMLDocument
	 * {@link https://www.w3.org/TR/DOM-Level-3-Core/references.html#DOM2HTML DOM Level 2 HTML},
	 * can be used to obtain specific types of {@link Document} objects.
	 *
	 * __It behaves slightly different from the description in the living standard__:
	 * - There is no interface/class `XMLDocument`, it returns a `Document`
	 * instance (with it's `type` set to `'xml'`).
	 * - `encoding`, `mode`, `origin`, `url` fields are currently not declared.
	 *
	 * @function DOMImplementation.createDocument
	 * @param {string | null} namespaceURI
	 * The
	 * {@link https://www.w3.org/TR/DOM-Level-3-Core/glossary.html#dt-namespaceURI namespace URI}
	 * of the document element to create or null.
	 * @param {string | null} qualifiedName
	 * The
	 * {@link https://www.w3.org/TR/DOM-Level-3-Core/glossary.html#dt-qualifiedname qualified name}
	 * of the document element to be created or null.
	 * @param {DocumentType | null} [doctype=null]
	 * The type of document to be created or null. When doctype is not null, its
	 * {@link Node#ownerDocument} attribute is set to the document being created. Default is
	 * `null`
	 * @returns {Document}
	 * A new {@link Document} object with its document element. If the NamespaceURI,
	 * qualifiedName, and doctype are null, the returned {@link Document} is empty with no
	 * document element.
	 * @throws {DOMException}
	 * With code:
	 *
	 * - `INVALID_CHARACTER_ERR`: Raised if the specified qualified name is not an XML name
	 * according to {@link https://www.w3.org/TR/DOM-Level-3-Core/references.html#XML XML 1.0}.
	 * - `NAMESPACE_ERR`: Raised if the qualifiedName is malformed, if the qualifiedName has a
	 * prefix and the namespaceURI is null, or if the qualifiedName is null and the namespaceURI
	 * is different from null, or if the qualifiedName has a prefix that is "xml" and the
	 * namespaceURI is different from "{@link http://www.w3.org/XML/1998/namespace}"
	 * {@link https://www.w3.org/TR/DOM-Level-3-Core/references.html#Namespaces XML Namespaces},
	 * or if the DOM implementation does not support the "XML" feature but a non-null namespace
	 * URI was provided, since namespaces were defined by XML.
	 * - `WRONG_DOCUMENT_ERR`: Raised if doctype has already been used with a different document
	 * or was created from a different implementation.
	 * - `NOT_SUPPORTED_ERR`: May be raised if the implementation does not support the feature
	 * "XML" and the language exposed through the Document does not support XML Namespaces (such
	 * as {@link https://www.w3.org/TR/DOM-Level-3-Core/references.html#HTML40 HTML 4.01}).
	 * @since DOM Level 2.
	 * @see {@link #createHTMLDocument}
	 * @see https://developer.mozilla.org/en-US/docs/Web/API/DOMImplementation/createDocument MDN
	 * @see https://dom.spec.whatwg.org/#dom-domimplementation-createdocument DOM Living Standard
	 * @see https://www.w3.org/TR/DOM-Level-3-Core/core.html#Level-2-Core-DOM-createDocument DOM
	 *      Level 3 Core
	 * @see https://www.w3.org/TR/DOM-Level-2-Core/core.html#Level-2-Core-DOM-createDocument DOM
	 *      Level 2 Core (initial)
	 */
	createDocument: function (namespaceURI, qualifiedName, doctype) {
		var contentType = MIME_TYPE.XML_APPLICATION;
		if (namespaceURI === NAMESPACE.HTML) {
			contentType = MIME_TYPE.XML_XHTML_APPLICATION;
		} else if (namespaceURI === NAMESPACE.SVG) {
			contentType = MIME_TYPE.XML_SVG_IMAGE;
		}
		var doc = new Document(PDC, { contentType: contentType });
		doc.implementation = this;
		doc.childNodes = new NodeList();
		doc.doctype = doctype || null;
		if (doctype) {
			doc.appendChild(doctype);
		}
		if (qualifiedName) {
			var root = doc.createElementNS(namespaceURI, qualifiedName);
			doc.appendChild(root);
		}
		return doc;
	},
	/**
	 * Creates an empty DocumentType node. Entity declarations and notations are not made
	 * available. Entity reference expansions and default attribute additions do not occur.
	 *
	 * **This behavior is slightly different from the one in the specs**:
	 * - `encoding`, `mode`, `origin`, `url` fields are currently not declared.
	 * - `publicId` and `systemId` contain the raw data including any possible quotes,
	 *   so they can always be serialized back to the original value
	 * - `internalSubset` contains the raw string between `[` and `]` if present,
	 *   but is not parsed or validated in any form.
	 *
	 * @function DOMImplementation#createDocumentType
	 * @param {string} qualifiedName
	 * The {@link https://www.w3.org/TR/DOM-Level-3-Core/glossary.html#dt-qualifiedname qualified
	 * name} of the document type to be created.
	 * @param {string} [publicId]
	 * The external subset public identifier. Stored verbatim including surrounding quotes.
	 * When serialized with `requireWellFormed: true`, the serializer throws `InvalidStateError`
	 * if the value is non-empty and does not match the XML `PubidLiteral` production
	 * (W3C DOM Parsing §3.2.1.3; XML 1.0 production [12]). Creation-time validation is not
	 * enforced — deferred to a future breaking release.
	 * @param {string} [systemId]
	 * The external subset system identifier. Stored verbatim including surrounding quotes.
	 * When serialized with `requireWellFormed: true`, the serializer throws `InvalidStateError`
	 * if the value is non-empty and does not match the XML `SystemLiteral` production
	 * (W3C DOM Parsing §3.2.1.3; XML 1.0 production [11]). Creation-time validation is not
	 * enforced — deferred to a future breaking release.
	 * @param {string} [internalSubset]
	 * The internal subset or an empty string if it is not present. Stored verbatim.
	 * When serialized with `requireWellFormed: true`, the serializer throws `InvalidStateError`
	 * if the value contains `"]>"`. Creation-time validation is not enforced.
	 * @returns {DocumentType}
	 * A new {@link DocumentType} node with {@link Node#ownerDocument} set to null.
	 * @throws {DOMException}
	 * With code:
	 *
	 * - `INVALID_CHARACTER_ERR`: Raised if the specified qualified name is not an XML name
	 * according to {@link https://www.w3.org/TR/DOM-Level-3-Core/references.html#XML XML 1.0}.
	 * - `NAMESPACE_ERR`: Raised if the qualifiedName is malformed.
	 * - `NOT_SUPPORTED_ERR`: May be raised if the implementation does not support the feature
	 * "XML" and the language exposed through the Document does not support XML Namespaces (such
	 * as {@link https://www.w3.org/TR/DOM-Level-3-Core/references.html#HTML40 HTML 4.01}).
	 * @since DOM Level 2.
	 * @see https://developer.mozilla.org/en-US/docs/Web/API/DOMImplementation/createDocumentType
	 *      MDN
	 * @see https://dom.spec.whatwg.org/#dom-domimplementation-createdocumenttype DOM Living
	 *      Standard
	 * @see https://www.w3.org/TR/DOM-Level-3-Core/core.html#Level-3-Core-DOM-createDocType DOM
	 *      Level 3 Core
	 * @see https://www.w3.org/TR/DOM-Level-2-Core/core.html#Level-2-Core-DOM-createDocType DOM
	 *      Level 2 Core
	 * @see https://github.com/xmldom/xmldom/blob/master/CHANGELOG.md#050
	 * @see https://www.w3.org/TR/DOM-Level-2-Core/#core-ID-Core-DocType-internalSubset
	 * @prettierignore
	 */
	createDocumentType: function (qualifiedName, publicId, systemId, internalSubset) {
		validateQualifiedName(qualifiedName);
		var node = new DocumentType(PDC);
		node.name = qualifiedName;
		node.nodeName = qualifiedName;
		node.publicId = publicId || '';
		node.systemId = systemId || '';
		node.internalSubset = internalSubset || '';
		node.childNodes = new NodeList();

		return node;
	},
	/**
	 * Returns an HTML document, that might already have a basic DOM structure.
	 *
	 * __It behaves slightly different from the description in the living standard__:
	 * - If the first argument is `false` no initial nodes are added (steps 3-7 in the specs are
	 * omitted)
	 * - `encoding`, `mode`, `origin`, `url` fields are currently not declared.
	 *
	 * @param {string | false} [title]
	 * A string containing the title to give the new HTML document.
	 * @returns {Document}
	 * The HTML document.
	 * @since WHATWG Living Standard.
	 * @see {@link #createDocument}
	 * @see https://dom.spec.whatwg.org/#dom-domimplementation-createhtmldocument
	 * @see https://dom.spec.whatwg.org/#html-document
	 */
	createHTMLDocument: function (title) {
		var doc = new Document(PDC, { contentType: MIME_TYPE.HTML });
		doc.implementation = this;
		doc.childNodes = new NodeList();
		if (title !== false) {
			doc.doctype = this.createDocumentType('html');
			doc.doctype.ownerDocument = doc;
			doc.appendChild(doc.doctype);
			var htmlNode = doc.createElement('html');
			doc.appendChild(htmlNode);
			var headNode = doc.createElement('head');
			htmlNode.appendChild(headNode);
			if (typeof title === 'string') {
				var titleNode = doc.createElement('title');
				titleNode.appendChild(doc.createTextNode(title));
				headNode.appendChild(titleNode);
			}
			htmlNode.appendChild(doc.createElement('body'));
		}
		return doc;
	},
};

/**
 * The DOM Node interface is an abstract base class upon which many other DOM API objects are
 * based, thus letting those object types to be used similarly and often interchangeably. As an
 * abstract class, there is no such thing as a plain Node object. All objects that implement
 * Node functionality are based on one of its subclasses. Most notable are Document, Element,
 * and DocumentFragment.
 *
 * In addition, every kind of DOM node is represented by an interface based on Node. These
 * include Attr, CharacterData (which Text, Comment, CDATASection and ProcessingInstruction are
 * all based on), and DocumentType.
 *
 * In some cases, a particular feature of the base Node interface may not apply to one of its
 * child interfaces; in that case, the inheriting node may return null or throw an exception,
 * depending on circumstances. For example, attempting to add children to a node type that
 * cannot have children will throw an exception.
 *
 * **This behavior is slightly different from the in the specs**:
 * - unimplemented interfaces: `EventTarget`
 *
 * @class
 * @abstract
 * @param {Symbol} symbol
 * @see http://www.w3.org/TR/2000/REC-DOM-Level-2-Core-20001113/core.html#ID-1950641247
 * @see https://dom.spec.whatwg.org/#node
 * @prettierignore
 */
function Node(symbol) {
	checkSymbol(symbol);
}

Node.prototype = {
	/**
	 * The first child of this node.
	 *
	 * @type {Node | null}
	 */
	firstChild: null,
	/**
	 * The last child of this node.
	 *
	 * @type {Node | null}
	 */
	lastChild: null,
	/**
	 * The previous sibling of this node.
	 *
	 * @type {Node | null}
	 */
	previousSibling: null,
	/**
	 * The next sibling of this node.
	 *
	 * @type {Node | null}
	 */
	nextSibling: null,
	/**
	 * The parent node of this node.
	 *
	 * @type {Node | null}
	 */
	parentNode: null,
	/**
	 * The parent element of this node.
	 *
	 * @type {Element | null}
	 */
	get parentElement() {
		return this.parentNode && this.parentNode.nodeType === this.ELEMENT_NODE ? this.parentNode : null;
	},
	/**
	 * The child nodes of this node.
	 *
	 * @type {NodeList}
	 */
	childNodes: null,
	/**
	 * The document object associated with this node.
	 *
	 * @type {Document | null}
	 */
	ownerDocument: null,
	/**
	 * The value of this node.
	 *
	 * @type {string | null}
	 */
	nodeValue: null,
	/**
	 * The namespace URI of this node.
	 *
	 * @type {string | null}
	 */
	namespaceURI: null,
	/**
	 * The prefix of the namespace for this node.
	 *
	 * @type {string | null}
	 */
	prefix: null,
	/**
	 * The local part of the qualified name of this node.
	 *
	 * @type {string | null}
	 */
	localName: null,
	/**
	 * The baseURI is currently always `about:blank`,
	 * since that's what happens when you create a document from scratch.
	 *
	 * @type {'about:blank'}
	 */
	baseURI: 'about:blank',
	/**
	 * Is true if this node is part of a document.
	 *
	 * @type {boolean}
	 */
	get isConnected() {
		var rootNode = this.getRootNode();
		return rootNode && rootNode.nodeType === rootNode.DOCUMENT_NODE;
	},
	/**
	 * Checks whether `other` is an inclusive descendant of this node.
	 *
	 * @param {Node | null | undefined} other
	 * The node to check.
	 * @returns {boolean}
	 * True if `other` is an inclusive descendant of this node; false otherwise.
	 * @see https://dom.spec.whatwg.org/#dom-node-contains
	 */
	contains: function (other) {
		if (!other) return false;
		var parent = other;
		do {
			if (this === parent) return true;
			parent = parent.parentNode;
		} while (parent);
		return false;
	},
	/**
	 * @typedef GetRootNodeOptions
	 * @property {boolean} [composed=false]
	 */
	/**
	 * Searches for the root node of this node.
	 *
	 * **This behavior is slightly different from the in the specs**:
	 * - ignores `options.composed`, since `ShadowRoot`s are unsupported, always returns root.
	 *
	 * @param {GetRootNodeOptions} [options]
	 * @returns {Node}
	 * Root node.
	 * @see https://dom.spec.whatwg.org/#dom-node-getrootnode
	 * @see https://dom.spec.whatwg.org/#concept-shadow-including-root
	 */
	getRootNode: function (options) {
		var parent = this;
		do {
			if (!parent.parentNode) {
				return parent;
			}
			parent = parent.parentNode;
		} while (parent);
	},
	/**
	 * Checks whether the given node is equal to this node.
	 *
	 * Two nodes are equal when they have the same type, defining characteristics (for the type),
	 * and the same childNodes. The comparison is iterative to avoid stack overflows on
	 * deeply-nested trees. Attribute nodes of each Element pair are also pushed onto the stack
	 * and compared the same way.
	 *
	 * @param {Node} [otherNode]
	 * @returns {boolean}
	 * @see https://dom.spec.whatwg.org/#concept-node-equals
	 * @see ../docs/walk-dom.md.
	 */
	isEqualNode: function (otherNode) {
		if (!otherNode) return false;

		// Use an explicit {node, other} pair stack to avoid call-stack overflow on deep trees.
		// walkDOM cannot be used here — parallel two-tree traversal requires pairing
		// corresponding nodes at each step across both trees simultaneously.
		var stack = [{ node: this, other: otherNode }];
		while (stack.length > 0) {
			var pair = stack.pop();
			var node = pair.node;
			var other = pair.other;

			if (node.nodeType !== other.nodeType) return false;

			switch (node.nodeType) {
				case node.DOCUMENT_TYPE_NODE:
					if (node.name !== other.name) return false;
					if (node.publicId !== other.publicId) return false;
					if (node.systemId !== other.systemId) return false;
					break;
				case node.ELEMENT_NODE:
					if (node.namespaceURI !== other.namespaceURI) return false;
					if (node.prefix !== other.prefix) return false;
					if (node.localName !== other.localName) return false;
					if (node.attributes.length !== other.attributes.length) return false;
					for (var i = 0; i < node.attributes.length; i++) {
						var attr = node.attributes.item(i);
						var otherAttr = other.getAttributeNodeNS(attr.namespaceURI, attr.localName);
						if (!otherAttr) return false;
						stack.push({ node: attr, other: otherAttr });
					}
					break;
				case node.ATTRIBUTE_NODE:
					if (node.namespaceURI !== other.namespaceURI) return false;
					if (node.localName !== other.localName) return false;
					if (node.value !== other.value) return false;
					break;
				case node.PROCESSING_INSTRUCTION_NODE:
					if (node.target !== other.target || node.data !== other.data) return false;
					break;
				case node.TEXT_NODE:
				case node.CDATA_SECTION_NODE:
				case node.COMMENT_NODE:
					if (node.data !== other.data) return false;
					break;
			}

			if (node.childNodes.length !== other.childNodes.length) return false;

			// Push children in reverse order so index 0 is processed first (LIFO).
			for (var i = node.childNodes.length - 1; i >= 0; i--) {
				stack.push({ node: node.childNodes[i], other: other.childNodes[i] });
			}
		}

		return true;
	},
	/**
	 * Checks whether or not the given node is this node.
	 *
	 * @param {Node} [otherNode]
	 */
	isSameNode: function (otherNode) {
		return this === otherNode;
	},
	/**
	 * Inserts a node before a reference node as a child of this node.
	 *
	 * @param {Node} newChild
	 * The new child node to be inserted.
	 * @param {Node | null} refChild
	 * The reference node before which newChild will be inserted.
	 * @returns {Node}
	 * The new child node successfully inserted.
	 * @throws {DOMException}
	 * Throws a DOMException if inserting the node would result in a DOM tree that is not
	 * well-formed, or if `child` is provided but is not a child of `parent`.
	 * See {@link _insertBefore} for more details.
	 * @since Modified in DOM L2
	 */
	insertBefore: function (newChild, refChild) {
		return _insertBefore(this, newChild, refChild);
	},
	/**
	 * Replaces an old child node with a new child node within this node.
	 *
	 * @param {Node} newChild
	 * The new node that is to replace the old node.
	 * If it already exists in the DOM, it is removed from its original position.
	 * @param {Node} oldChild
	 * The existing child node to be replaced.
	 * @returns {Node}
	 * Returns the replaced child node.
	 * @throws {DOMException}
	 * Throws a DOMException if replacing the node would result in a DOM tree that is not
	 * well-formed, or if `oldChild` is not a child of `this`.
	 * This can also occur if the pre-replacement validity assertion fails.
	 * See {@link _insertBefore}, {@link Node.removeChild}, and
	 * {@link assertPreReplacementValidityInDocument} for more details.
	 * @see https://dom.spec.whatwg.org/#concept-node-replace
	 */
	replaceChild: function (newChild, oldChild) {
		_insertBefore(this, newChild, oldChild, assertPreReplacementValidityInDocument);
		if (oldChild) {
			this.removeChild(oldChild);
		}
	},
	/**
	 * Removes an existing child node from this node.
	 *
	 * @param {Node} oldChild
	 * The child node to be removed.
	 * @returns {Node}
	 * Returns the removed child node.
	 * @throws {DOMException}
	 * Throws a DOMException if `oldChild` is not a child of `this`.
	 * See {@link _removeChild} for more details.
	 */
	removeChild: function (oldChild) {
		return _removeChild(this, oldChild);
	},
	/**
	 * Appends a child node to this node.
	 *
	 * @param {Node} newChild
	 * The child node to be appended to this node.
	 * If it already exists in the DOM, it is removed from its original position.
	 * @returns {Node}
	 * Returns the appended child node.
	 * @throws {DOMException}
	 * Throws a DOMException if appending the node would result in a DOM tree that is not
	 * well-formed, or if `newChild` is not a valid Node.
	 * See {@link insertBefore} for more details.
	 */
	appendChild: function (newChild) {
		return this.insertBefore(newChild, null);
	},
	/**
	 * Determines whether this node has any child nodes.
	 *
	 * @returns {boolean}
	 * Returns true if this node has any child nodes, and false otherwise.
	 */
	hasChildNodes: function () {
		return this.firstChild != null;
	},
	/**
	 * Creates a copy of the calling node.
	 *
	 * @param {boolean} deep
	 * If true, the contents of the node are recursively copied.
	 * If false, only the node itself (and its attributes, if it is an element) are copied.
	 * @returns {Node}
	 * Returns the newly created copy of the node.
	 * @throws {DOMException}
	 * May throw a DOMException if operations within {@link Element#setAttributeNode} or
	 * {@link Node#appendChild} (which are potentially invoked in this method) do not meet their
	 * specific constraints.
	 * @see {@link cloneNode}
	 */
	cloneNode: function (deep) {
		return cloneNode(this.ownerDocument || this, this, deep);
	},
	/**
	 * Puts the specified node and all of its subtree into a "normalized" form. In a normalized
	 * subtree, no text nodes in the subtree are empty and there are no adjacent text nodes.
	 *
	 * Specifically, this method merges any adjacent text nodes (i.e., nodes for which `nodeType`
	 * is `TEXT_NODE`) into a single node with the combined data. It also removes any empty text
	 * nodes.
	 *
	 * This method iterativly traverses all child nodes to normalize all descendent nodes within
	 * the subtree.
	 *
	 * @throws {DOMException}
	 * May throw a DOMException if operations within removeChild or appendData (which are
	 * potentially invoked in this method) do not meet their specific constraints.
	 * @since Modified in DOM Level 2
	 * @see {@link Node.removeChild}
	 * @see {@link CharacterData.appendData}
	 * @see ../docs/walk-dom.md.
	 */
	normalize: function () {
		walkDOM(this, null, {
			enter: function (node) {
				// Merge adjacent text children of node before walkDOM schedules them.
				// walkDOM reads lastChild/previousSibling after enter returns, so the
				// surviving post-merge children are what it descends into.
				var child = node.firstChild;
				while (child) {
					var next = child.nextSibling;
					if (next !== null && next.nodeType === TEXT_NODE && child.nodeType === TEXT_NODE) {
						node.removeChild(next);
						child.appendData(next.data);
						// Do not advance child: re-check new nextSibling for another text run
					} else {
						child = next;
					}
				}
				return true; // descend into surviving children
			},
		});
	},
	/**
	 * Checks whether the DOM implementation implements a specific feature and its version.
	 *
	 * @deprecated
	 * Since `DOMImplementation.hasFeature` is deprecated and always returns true.
	 * @param {string} feature
	 * The package name of the feature to test. This is the same name that can be passed to the
	 * method `hasFeature` on `DOMImplementation`.
	 * @param {string} version
	 * This is the version number of the package name to test.
	 * @returns {boolean}
	 * Returns true in all cases in the current implementation.
	 * @since Introduced in DOM Level 2
	 * @see {@link DOMImplementation.hasFeature}
	 */
	isSupported: function (feature, version) {
		return this.ownerDocument.implementation.hasFeature(feature, version);
	},
	/**
	 * Look up the prefix associated to the given namespace URI, starting from this node.
	 * **The default namespace declarations are ignored by this method.**
	 * See Namespace Prefix Lookup for details on the algorithm used by this method.
	 *
	 * **This behavior is different from the in the specs**:
	 * - no node type specific handling
	 * - uses the internal attribute _nsMap for resolving namespaces that is updated when changing attributes
	 *
	 * @param {string | null} namespaceURI
	 * The namespace URI for which to find the associated prefix.
	 * @returns {string | null}
	 * The associated prefix, if found; otherwise, null.
	 * @see https://www.w3.org/TR/DOM-Level-3-Core/core.html#Node3-lookupNamespacePrefix
	 * @see https://www.w3.org/TR/DOM-Level-3-Core/namespaces-algorithms.html#lookupNamespacePrefixAlgo
	 * @see https://dom.spec.whatwg.org/#dom-node-lookupprefix
	 * @see https://github.com/xmldom/xmldom/issues/322
	 * @prettierignore
	 */
	lookupPrefix: function (namespaceURI) {
		var el = this;
		while (el) {
			var map = el._nsMap;
			//console.dir(map)
			if (map) {
				for (var n in map) {
					if (hasOwn(map, n) && map[n] === namespaceURI) {
						return n;
					}
				}
			}
			el = el.nodeType == ATTRIBUTE_NODE ? el.ownerDocument : el.parentNode;
		}
		return null;
	},
	/**
	 * This function is used to look up the namespace URI associated with the given prefix,
	 * starting from this node.
	 *
	 * **This behavior is different from the in the specs**:
	 * - no node type specific handling
	 * - uses the internal attribute _nsMap for resolving namespaces that is updated when changing attributes
	 *
	 * @param {string | null} prefix
	 * The prefix for which to find the associated namespace URI.
	 * @returns {string | null}
	 * The associated namespace URI, if found; otherwise, null.
	 * @since DOM Level 3
	 * @see https://dom.spec.whatwg.org/#dom-node-lookupnamespaceuri
	 * @see https://www.w3.org/TR/DOM-Level-3-Core/core.html#Node3-lookupNamespaceURI
	 * @prettierignore
	 */
	lookupNamespaceURI: function (prefix) {
		var el = this;
		while (el) {
			var map = el._nsMap;
			//console.dir(map)
			if (map) {
				if (hasOwn(map, prefix)) {
					return map[prefix];
				}
			}
			el = el.nodeType == ATTRIBUTE_NODE ? el.ownerDocument : el.parentNode;
		}
		return null;
	},
	/**
	 * Determines whether the given namespace URI is the default namespace.
	 *
	 * The function works by looking up the prefix associated with the given namespace URI. If no
	 * prefix is found (i.e., the namespace URI is not registered in the namespace map of this
	 * node or any of its ancestors), it returns `true`, implying the namespace URI is considered
	 * the default.
	 *
	 * **This behavior is dif