feat: add iterator function to NodeList and NamedNodeMap (#634)

Closes #633
xmldom · Mar 17, 2024 · 6b21971 · 6b21971
1 parent 91039af
commit 6b21971
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diff --git a/lib/dom.js b/lib/dom.js
@@ -294,6 +294,7 @@ function docGUID(doc) {
  * 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
@@ -361,6 +362,30 @@ NodeList.prototype = {
 		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
@@ -667,6 +692,30 @@ NamedNodeMap.prototype = {
 		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

diff --git a/test/dom/named-node-map.test.js b/test/dom/named-node-map.test.js
@@ -7,6 +7,63 @@ const HTML_OWNER_ELEMENT = { _isInHTMLDocumentAndNamespace: () => true };
 const XML_OWNER_ELEMENT = { _isInHTMLDocumentAndNamespace: () => false };
 
 describe('NamedNodeMap', () => {
+	describe('Iterator', () => {
+		test('should iterate over 3/3 items when using a for...of loop without interruption', () => {
+			const it = new NamedNodeMap();
+			const first = new Attr();
+			it[0] = first;
+			const second = new Attr();
+			it[1] = second;
+			const third = new Attr();
+			it[2] = third;
+			it.length = 3;
+
+			let count = 0;
+			for (const _item of it) {
+				count++;
+			}
+			expect(count).toBe(it.length);
+		});
+		test('should iterate over 1/3 items when using a for...of loop and breaking after first iteration', () => {
+			const it = new NamedNodeMap();
+			const first = new Attr();
+			it[0] = first;
+			const second = new Attr();
+			it[1] = second;
+			const third = new Attr();
+			it[2] = third;
+			it.length = 3;
+
+			let count = 0;
+			for (const _item of it) {
+				count++;
+				break;
+			}
+			expect(count).toBe(1);
+		});
+		test('should iterate over 3/3 items when using two for...of loops subsequently', () => {
+			const it = new NamedNodeMap();
+			const first = new Attr();
+			it[0] = first;
+			const second = new Attr();
+			it[1] = second;
+			const third = new Attr();
+			it[2] = third;
+			it.length = 3;
+
+			let firstCount = 0;
+			for (const _item of it) {
+				firstCount++;
+			}
+			let secondCount = 0;
+			for (const _item of it) {
+				secondCount++;
+			}
+
+			expect(firstCount).toBe(it.length);
+			expect(secondCount).toBe(it.length);
+		});
+	});
 	describe('getNamedItem', () => {
 		test('should return null when no attribute is found', () => {
 			const it = new NamedNodeMap();

diff --git a/test/dom/node-list.test.js b/test/dom/node-list.test.js
@@ -1,9 +1,66 @@
 'use strict';
 
 const { describe, expect, test } = require('@jest/globals');
-const { NodeList, LiveNodeList, DOMImplementation } = require('../../lib/dom');
+const { NodeList, LiveNodeList, DOMImplementation, Element } = require('../../lib/dom');
 
 describe('NodeList', () => {
+	describe('Iterator', () => {
+		test('should iterate over 3/3 items when using a for...of loop without interruption', () => {
+			const it = new NodeList();
+			const first = new Element();
+			it[0] = first;
+			const second = new Element();
+			it[1] = second;
+			const third = new Element();
+			it[2] = third;
+			it.length = 3;
+
+			let count = 0;
+			for (const _item of it) {
+				count++;
+			}
+			expect(count).toBe(it.length);
+		});
+		test('should iterate over 1/3 items when using a for...of loop and breaking after first iteration', () => {
+			const it = new NodeList();
+			const first = new Element();
+			it[0] = first;
+			const second = new Element();
+			it[1] = second;
+			const third = new Element();
+			it[2] = third;
+			it.length = 3;
+
+			let count = 0;
+			for (const _item of it) {
+				count++;
+				break;
+			}
+			expect(count).toBe(1);
+		});
+		test('should iterate over 3/3 items when using two for...of loops subsequently', () => {
+			const it = new NodeList();
+			const first = new Element();
+			it[0] = first;
+			const second = new Element();
+			it[1] = second;
+			const third = new Element();
+			it[2] = third;
+			it.length = 3;
+
+			let firstCount = 0;
+			for (const _item of it) {
+				firstCount++;
+			}
+			let secondCount = 0;
+			for (const _item of it) {
+				secondCount++;
+			}
+
+			expect(firstCount).toBe(it.length);
+			expect(secondCount).toBe(it.length);
+		});
+	});
 	describe('item', () => {
 		test('should return null for items outside length', () => {
 			const it = new NodeList();