# Fast HTML Parser [![NPM version](https://badge.fury.io/js/node-html-parser.png)](http://badge.fury.io/js/node-html-parser) [![Build Status](https://img.shields.io/endpoint.svg?url=https%3A%2F%2Factions-badge.atrox.dev%2Ftaoqf%2Fnode-html-parser%2Fbadge%3Fref%3Dmain&style=flat)](https://actions-badge.atrox.dev/taoqf/node-html-parser/goto?ref=main)

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 `<td>` etc).

## Install

```shell
npm 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

```shell
html-parser     :24.1595 ms/file ± 18.7667
htmljs-parser   :4.72064 ms/file ± 5.67689
html-dom-parser :2.18055 ms/file ± 2.96136
html5parser     :1.69639 ms/file ± 2.17111
cheerio         :12.2122 ms/file ± 8.10916
parse5          :6.50626 ms/file ± 4.02352
htmlparser2     :2.38179 ms/file ± 3.42389
htmlparser      :17.4820 ms/file ± 128.041
high5           :3.95188 ms/file ± 2.52313
node-html-parser:2.04288 ms/file ± 1.25203
node-html-parser (last release):2.00527 ms/file ± 1.21317
```

Tested with [htmlparser-benchmark](https://github.com/AndreasMadsen/htmlparser-benchmark).

## Usage

```ts
import { parse } from 'node-html-parser';

const root = parse('<ul id="list"><li>Hello World</li></ul>');

// parse() adds a wrapper node, so the input data's first node is the root's first child node
console.log(root.firstChild.structure);
// ul#list
//   li
//     #text

console.log(root.querySelector('#list'));
// { tagName: 'ul',
//   rawAttrs: 'id="list"',
//   childNodes:
//    [ { tagName: 'li',
//        rawAttrs: '',
//        childNodes: [Object],
//        classNames: [] } ],
//   id: 'list',
//   classNames: [] }
console.log(root.toString());
// <ul id="list"><li>Hello World</li></ul>
root.set_content('<li>Hello World</li>');
root.toString();	// <li>Hello World</li>
```

```js
var HTMLParser = require('node-html-parser');

var root = HTMLParser.parse('<ul id="list"><li>Hello World</li></ul>');
```

## Global Methods

### parse(data[, options])

Parse the data provided, wrap the result in a new node, and return the root of the generated DOM.

- **data**, data to parse
- **options**, parse options

  ```js
  {
    lowerCaseTagName: false,		// convert tag name to lower case (hurts performance heavily)
    comment: false,           		// retrieve comments (hurts performance slightly)
    fixNestedATags: false,    		// fix invalid nested <a> HTML tags 
    parseNoneClosedTags: false, 	// close none closed HTML tags instead of removing them 
    preserveTagNesting: false,		// preserve invalid HTML nesting instead of auto-closing tags (e.g. <p><p>bar</p></p>)
    voidTag: {
      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']
      closingSlash: true	// optional, default false. void tag serialisation, add a final slash <br/>
    },
    blockTextElements: {
      script: true,		// keep text content when parsing
      noscript: true,		// keep text content when parsing
      style: true,		// keep text content when parsing
      pre: true			// keep text content when parsing
    },
    closeAllOnClosing: false  // Close all non-closed tags when containing element closes
  }
  ```

### valid(data[, options])

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

## Class

```mermaid
classDiagram
direction TB
class HTMLElement{
	this trimRight()
	this removeWhitespace()
	Node[] querySelectorAll(string selector)
	Node querySelector(string selector)
	boolean matches(string selector)
	HTMLElement[] getElementsByTagName(string tagName)
	Node closest(string selector)
	Node appendChild(Node node)
	this insertAdjacentHTML('beforebegin' | 'afterbegin' | 'beforeend' | 'afterend' where, string html)
	this setAttribute(string key, string value)
	this setAttributes(Record string, string attrs)
	this removeAttribute(string key)
	string getAttribute(string key)
	this exchangeChild(Node oldNode, Node newNode)
	this removeChild(Node node)
	string toString()
	this set_content(string content)
	this set_content(Node content)
	this set_content(Node[] content)
	this remove()
	this replaceWith((string | Node)[] ...nodes)
	ClassList classList
	HTMLElement clone()
	HTMLElement getElementById(string id)
	string text
	string rawText
	string tagName
	string structuredText
	string structure
	Node firstChild
	Node lastChild
	Node nextSibling
	HTMLElement nextElementSibling
	Node previousSibling
	HTMLElement previousElementSibling
	string innerHTML
	string outerHTML
	string textContent
	Record<string, string> attributes
	[number, number] range
}
class Node{
	<<abstract>>
	string toString()
	Node clone()
	this remove()
	number nodeType
	string innerText
	string textContent
}
class ClassList{
	add(string c)
	replace(string c1, string c2)
	remove(string c)
	toggle(string c)
	boolean contains(string c)
	number length
	string[] value
	string toString()
}
class CommentNode{
	CommentNode clone()
	string toString()
}
class TextNode{
	TextNode clone()
	string toString()
	string rawText
	string trimmedRawText
	string trimmedText
	string text
	boolean isWhitespace
}
Node --|> HTMLElement
Node --|> CommentNode
Node --|> TextNode
Node ..> 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.

### matches(selector)

Tests whether the node matches a given CSS selector.

### 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](#htmlelementouterhtml)

### 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
`&amp;` 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 of the wrapper node added by `parse()`. `undefined` if the node has no children.

### lastChild

Get last child node of the wrapper node added by `parse()`. `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](#htmlelementset_contentcontent-string--node--node).

### 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 ])
