Fast HTML Parser

Fast HTML Parser is a very fast HTML parser. Which will generate a simplified DOM tree, with element query support.

Per the design, it intends to parse massive HTML files in lowest price, thus the performance is the top priority. For this reason, some malformatted HTML may not be able to parse correctly, but most usual errors are covered (eg. HTML4 style no closing <li>, <td> etc).

Install

1npm install --save node-html-parser

Note: when using Fast HTML Parser in a Typescript project the minimum Typescript version supported is ^4.1.2.

Performance

-- 2022-08-10

1html-parser     :24.1595 ms/file ± 18.7667
2htmljs-parser   :4.72064 ms/file ± 5.67689
3html-dom-parser :2.18055 ms/file ± 2.96136
4html5parser     :1.69639 ms/file ± 2.17111
5cheerio         :12.2122 ms/file ± 8.10916
6parse5          :6.50626 ms/file ± 4.02352
7htmlparser2     :2.38179 ms/file ± 3.42389
8htmlparser      :17.4820 ms/file ± 128.041
9high5           :3.95188 ms/file ± 2.52313
10node-html-parser:2.04288 ms/file ± 1.25203
11node-html-parser (last release):2.00527 ms/file ± 1.21317

Tested with htmlparser-benchmark.

Usage

1import { parse } from 'node-html-parser';
2
3const root = parse('<ul id="list"><li>Hello World</li></ul>');
4
5console.log(root.firstChild.structure);
6// ul#list
7//   li
8//     #text
9
10console.log(root.querySelector('#list'));
11// { tagName: 'ul',
12//   rawAttrs: 'id="list"',
13//   childNodes:
14//    [ { tagName: 'li',
15//        rawAttrs: '',
16//        childNodes: [Object],
17//        classNames: [] } ],
18//   id: 'list',
19//   classNames: [] }
20console.log(root.toString());
21// <ul id="list"><li>Hello World</li></ul>
22root.set_content('<li>Hello World</li>');
23root.toString();	// <li>Hello World</li>

1var HTMLParser = require('node-html-parser');
2
3var root = HTMLParser.parse('<ul id="list"><li>Hello World</li></ul>');

Global Methods

parse(data[, options])

Parse the data provided, and return the root of the generated DOM.

• data, data to parse

• options, parse options

  1{
  2  lowerCaseTagName: false,		// convert tag name to lower case (hurts performance heavily)
  3  comment: false,           		// retrieve comments (hurts performance slightly)
  4  fixNestedATags: false,    		// fix invalid nested <a> HTML tags 
  5  parseNoneClosedTags: false, 	// close none closed HTML tags instead of removing them 
  6  voidTag: {
  7    tags: ['area', 'base', 'br', 'col', 'embed', 'hr', 'img', 'input', 'link', 'meta', 'param', 'source', 'track', 'wbr'],	// optional and case insensitive, default value is ['area', 'base', 'br', 'col', 'embed', 'hr', 'img', 'input', 'link', 'meta', 'param', 'source', 'track', 'wbr']
  8    closingSlash: true	// optional, default false. void tag serialisation, add a final slash <br/>
  9  },
  10  blockTextElements: {
  11    script: true,		// keep text content when parsing
  12    noscript: true,		// keep text content when parsing
  13    style: true,		// keep text content when parsing
  14    pre: true			// keep text content when parsing
  15  }
  16}

valid(data[, options])

Parse the data provided, return true if the given data is valid, and return false if not.

Class

1classDiagram
2direction TB
3class HTMLElement{
4	this trimRight()
5	this removeWhitespace()
6	Node[] querySelectorAll(string selector)
7	Node querySelector(string selector)
8	HTMLElement[] getElementsByTagName(string tagName)
9	Node closest(string selector)
10	Node appendChild(Node node)
11	this insertAdjacentHTML('beforebegin' | 'afterbegin' | 'beforeend' | 'afterend' where, string html)
12	this setAttribute(string key, string value)
13	this setAttributes(Record string, string attrs)
14	this removeAttribute(string key)
15	string getAttribute(string key)
16	this exchangeChild(Node oldNode, Node newNode)
17	this removeChild(Node node)
18	string toString()
19	this set_content(string content)
20	this set_content(Node content)
21	this set_content(Node[] content)
22	this remove()
23	this replaceWith((string | Node)[] ...nodes)
24	ClassList classList
25	HTMLElement clone()
26	HTMLElement getElementById(string id)
27	string text
28	string rawText
29	string tagName
30	string structuredText
31	string structure
32	Node firstChild
33	Node lastChild
34	Node nextSibling
35	HTMLElement nextElementSibling
36	Node previousSibling
37	HTMLElement previousElementSibling
38	string innerHTML
39	string outerHTML
40	string textContent
41	Record<string, string> attributes
42	[number, number] range
43}
44class Node{
45	<<abstract>>
46	string toString()
47	Node clone()
48	this remove()
49	number nodeType
50	string innerText
51	string textContent
52}
53class ClassList{
54	add(string c)
55	replace(string c1, string c2)
56	remove(string c)
57	toggle(string c)
58	boolean contains(string c)
59	number length
60	string[] value
61	string toString()
62}
63class CommentNode{
64	CommentNode clone()
65	string toString()
66}
67class TextNode{
68	TextNode clone()
69	string toString()
70	string rawText
71	string trimmedRawText
72	string trimmedText
73	string text
74	boolean isWhitespace
75}
76Node --|> HTMLElement
77Node --|> CommentNode
78Node --|> TextNode
79Node ..> ClassList

HTMLElement Methods

trimRight()

Trim element from right (in block) after seeing pattern in a TextNode.

removeWhitespace()

Remove whitespaces in this sub tree.

querySelectorAll(selector)

Query CSS selector to find matching nodes.

Note: Full range of CSS3 selectors supported since v3.0.0.

querySelector(selector)

Query CSS Selector to find matching node. null if not found.

getElementsByTagName(tagName)

Get all elements with the specified tagName.

Note: Use * for all elements.

closest(selector)

Query closest element by css selector. null if not found.

before(...nodesOrStrings)

Insert one or multiple nodes or text before the current element. Does not work on root.

after(...nodesOrStrings)

Insert one or multiple nodes or text after the current element. Does not work on root.

prepend(...nodesOrStrings)

Insert one or multiple nodes or text to the first position of an element's child nodes.

append(...nodesOrStrings)

Insert one or multiple nodes or text to the last position of an element's child nodes. This is similar to appendChild, but accepts arbitrarily many nodes and converts strings to text nodes.

appendChild(node)

Append a node to an element's child nodes.

insertAdjacentHTML(where, html)

Parses the specified text as HTML and inserts the resulting nodes into the DOM tree at a specified position.

setAttribute(key: string, value: string)

Set value to key attribute.

setAttributes(attrs: Record<string, string>)

Set attributes of the element.

removeAttribute(key: string)

Remove key attribute.

getAttribute(key: string)

Get key attribute. undefined if not set.

exchangeChild(oldNode: Node, newNode: Node)

Exchanges given child with new child.

removeChild(node: Node)

Remove child node.

toString()

Same as outerHTML

set_content(content: string | Node | Node[])

Set content. Notice: Do not set content of the root node.

remove()

Remove current element.

replaceWith(...nodes: (string | Node)[])

Replace current element with other node(s).

classList

classList.add

Add class name.

classList.replace(old: string, new: string)

Replace class name with another one.

classList.remove()

Remove class name.

classList.toggle(className: string):void

Toggle class. Remove it if it is already included, otherwise add.

classList.contains(className: string): boolean

Returns true if the classname is already in the classList.

classList.value

Get class names.

clone()

Clone a node.

getElementById(id: string): HTMLElement | null

Get element by it's ID.

HTMLElement Properties

text

Get unescaped text value of current node and its children. Like innerText. (slow for the first time)

rawText

Get escaped (as-is) text value of current node and its children. May have & in it. (fast)

tagName

Get or Set tag name of HTMLElement. Note that the returned value is an uppercase string.

structuredText

Get structured Text.

structure

Get DOM structure.

childNodes

Get all child nodes. A child node can be a TextNode, a CommentNode and a HTMLElement.

children

Get all child elements, so all child nodes of type HTMLELement.

firstChild

Get first child node. undefined if the node has no children.

lastChild

Get last child node. undefined if the node has no children.

firstElementChild

Get the first child of type HTMLElement. undefined if none exists.

lastElementChild

Get the first child of type HTMLElement. undefined if none exists.

childElementCount

Get the number of children that are of type HTMLElement.

innerHTML

Set or Get innerHTML.

outerHTML

Get outerHTML.

nextSibling

Returns a reference to the next child node of the current element's parent. null if not found.

nextElementSibling

Returns a reference to the next child element of the current element's parent. null if not found.

previousSibling

Returns a reference to the previous child node of the current element's parent. null if not found.

previousElementSibling

Returns a reference to the previous child element of the current element's parent. null if not found.

textContent

Get or Set textContent of current element, more efficient than set_content.

attributes

Get all attributes of current element. Notice: do not try to change the returned value.

range

Corresponding source code start and end indexes (ie [ 0, 40 ])