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    @desertnet/html-parser

    1.0.1 • Public • Published

    html-parser

    This HTML parser and validator is not a strict HTML parser in the vein of the XHTML strict validators of old. Instead, it aims to parse HTML as browsers do and only surface errors that are likely to confuse browsers or that are indicative of a confused HTML author.

    Installation

    npm install --save @desertnet/html-parser

    Usage

    const HTMLParser = require('@desertnet/html-parser')
    
    const html = `
    <p>
      <b>I forgot to close my b tag.
    </p>
    
    <p>
      I&npsb;misspelled the no-break-space entity.
    </p>
    `.trim()
    
    const errors = HTMLParser.validate(html)
    
    errors.forEach(error => {
      console.log(`${error.message} (line: ${error.line}, column: ${error.column})`)
    })

    Outputs:

    Could not find closing tag for "<b>". (line: 2, column: 3)
    Unexpected closing tag, "</p>". Expected closing tag for "<b>". (line: 3, column: 1)
    Invalid HTML entity name for "&npsb;". (line: 6, column: 5)
    

    API

    HTMLParser.validate(htmlString)

    Static method on HTMLParser constructor. It parses the HTML fragment in htmlString and returns an array of HTMLParseErrors. If there were no errors, an empty array is returned.

    HTMLParser

    The HTMLParser constructor. It takes no arguments.

    const parser = new HTMLParser()

    .parse(htmlString)

    Parses the HTML fragment in htmlString and returns an HTMLNode object containing the parsed HTML.

    const parseTree = parser.parse('<h1>Hello world!</h1>')

    HTMLParseError

    Represents an error discovered durning parsing of an HTML fragment.

    parseTree.errors.forEach(error => {
      console.log(`${error.message} (line: ${error.line}, column: ${error.column})`)
    })

    .message

    Property that is a string containing an English description of the error.

    .startIndex

    Property that is a number indicating the index into the source string where the error begins.

    .endIndex

    Property that is a number indicating the index into the source string where the error ends.

    .line

    Property that is a number indicating the line number where the error begins. Line numbers being at 1, not 0.

    .column

    Property that is a number indicating the column of the line where the error begins. Columns also begin at 1, not 0.

    HTMLNode

    The base class for all node types. Returned by HTMLParser's .parse method.

    console.log(indentedNodeList(parseTree))
    
    function indentedNodeList (node, indent = '') {
      let str = ''
      if (node.children) {
        str += node.children.reduce((prev, child) => {
          return prev + indentedNodeList(child, `${indent}  `)
        }, '')
      }
      return `${indent}${node.type}\n${str}`
    }

    .type

    Property indicating the type of node. It will be one of the following strings:

    • ROOT: Root node of the tree.
    • TAG: An HTML tag.
    • ATTRIBUTE: An attribute of an HTML tag.
    • TEXT: A text content node.
    • ENTITY: An HTML entity (i.e. &amp;)
    • COMMENT: An HTML comment tag.
    • CLOSETAG: A closing HTML tag.

    .children

    Property that is either null, or an array of HTMLNodes that are the node's children.

    .indexRange

    Property that, if non-null, will be an array of two numbers. The first is the index of the source string where the node begins, and the second is the index of the source string where the node ends.

    .errors

    Property that is an array of HTMLParseErrors associated with this node and its descendants.

    .ownErrors

    Property that is an array of HTMLParseErrors associated with only this node (not its descendants).

    .tagName

    On TAG and CLOSETAG type nodes, this is a string of the lowercased tag name.

    .attributes

    On TAG type nodes, this is an array of ATTRIBUTE nodes that belong to the tag.

    .closingTag

    On TAG type nodes, this is a CLOSETAG node, if a closing tag for this node was found.

    Install

    npm i @desertnet/html-parser

    DownloadsWeekly Downloads

    1,237

    Version

    1.0.1

    License

    MIT

    Unpacked Size

    463 kB

    Total Files

    40

    Last publish

    Collaborators

    • limulus