turndown/lib/turndown.browser.es.js

A library that converts HTML to Markdown

function extend (destination) {
  for (var i = 1; i < arguments.length; i++) {
    var source = arguments[i];
    for (var key in source) {
      if (source.hasOwnProperty(key)) destination[key] = source[key];
    }
  }
  return destination
}

function repeat (character, count) {
  return Array(count + 1).join(character)
}

function isBlock (node) {
  return [
    'address', 'article', 'aside', 'audio', 'blockquote', 'body', 'canvas',
    'center', 'dd', 'dir', 'div', 'dl', 'dt', 'fieldset', 'figcaption',
    'figure', 'footer', 'form', 'frameset', 'h1', 'h2', 'h3', 'h4', 'h5', 'h6',
    'header', 'hgroup', 'hr', 'html', 'isindex', 'li', 'main', 'menu', 'nav',
    'noframes', 'noscript', 'ol', 'output', 'p', 'pre', 'section', 'table',
    'tbody', 'td', 'tfoot', 'th', 'thead', 'tr', 'ul'
  ].indexOf(node.nodeName.toLowerCase()) !== -1
}

var converters = {};

converters.paragraph = {
  filter: 'p',

  replacement: function (content) {
    return '\n\n' + content + '\n\n'
  }
};

converters.lineBreak = {
  filter: 'br',

  replacement: function () {
    return '  \n'
  }
};

converters.heading = {
  filter: ['h1', 'h2', 'h3', 'h4', 'h5', 'h6'],

  replacement: function (content, node, options) {
    var hLevel = Number(node.nodeName.charAt(1));

    if (options.headingStyle === 'setext' && hLevel < 3) {
      var underline = repeat((hLevel === 1 ? '=' : '-'), content.length);
      return (
        '\n\n' + content + '\n' + underline + '\n\n'
      )
    } else {
      return '\n\n' + repeat('#', hLevel) + ' ' + content + '\n\n'
    }
  }
};

converters.blockquote = {
  filter: 'blockquote',

  replacement: function (content) {
    content = content.replace(/^\n+|\n+$/g, '');
    content = content.replace(/^/gm, '> ');
    return '\n\n' + content + '\n\n'
  }
};

converters.list = {
  filter: ['ul', 'ol'],

  replacement: function (content, node) {
    var parent = node.parentNode;
    if (parent.nodeName === 'LI' && parent.lastElementChild === node) {
      return '\n' + content
    } else {
      return '\n\n' + content + '\n\n'
    }
  }
};

converters.listItem = {
  filter: 'li',

  replacement: function (content, node, options) {
    content = content
      .replace(/^\n+/, '') // remove leading newlines
      .replace(/\n+$/, '\n') // replace trailing newlines with just a single one
      .replace(/\n/gm, '\n    '); // indent
    var prefix = options.bulletListMarker + '   ';
    var parent = node.parentNode;
    if (parent.nodeName === 'OL') {
      var start = parent.getAttribute('start');
      var index = Array.prototype.indexOf.call(parent.children, node);
      prefix = (start ? Number(start) + index : index + 1) + '.  ';
    }
    return (
      prefix + content + (node.nextSibling && !/\n$/.test(content) ? '\n' : '')
    )
  }
};

converters.indentedCodeBlock = {
  filter: function (node, options) {
    return (
      options.codeBlockStyle === 'indented' &&
      node.nodeName === 'PRE' &&
      node.firstChild.nodeName === 'CODE'
    )
  },

  replacement: function (content, node, options) {
    return (
      '\n\n    ' +
      node.firstChild.textContent.replace(/\n/g, '\n    ') +
      '\n\n'
    )
  }
};

converters.fencedCodeBlock = {
  filter: function (node, options) {
    return (
      options.codeBlockStyle === 'fenced' &&
      node.nodeName === 'PRE' &&
      node.firstChild.nodeName === 'CODE'
    )
  },

  replacement: function (content, node, options) {
    var className = node.firstChild.className || '';
    var language = (className.match(/language-(\S+)/) || [null, ''])[1];

    return (
      '\n\n' + options.fence + language + '\n' +
      node.firstChild.textContent +
      '\n' + options.fence + '\n\n'
    )
  }
};

converters.horizontalRule = {
  filter: 'hr',

  replacement: function (content, node, options) {
    return '\n\n' + options.hr + '\n\n'
  }
};

converters.inlineLink = {
  filter: function (node, options) {
    return (
      options.linkStyle === 'inlined' &&
      node.nodeName === 'A' &&
      node.getAttribute('href')
    )
  },

  replacement: function (content, node) {
    var href = node.getAttribute('href');
    var title = node.title ? ' "' + node.title + '"' : '';
    return '[' + content + '](' + href + title + ')'
  }
};

converters.referenceLink = {
  filter: function (node, options) {
    return (
      options.linkStyle === 'referenced' &&
      node.nodeName === 'A' &&
      node.getAttribute('href')
    )
  },

  replacement: function (content, node, options) {
    var href = node.getAttribute('href');
    var title = node.title ? ' "' + node.title + '"' : '';
    var replacement;
    var reference;

    switch (options.linkReferenceStyle) {
      case 'collapsed':
        replacement = '[' + content + '][]';
        reference = '[' + content + ']: ' + href + title;
        break
      case 'shortcut':
        replacement = '[' + content + ']';
        reference = '[' + content + ']: ' + href + title;
        break
      default:
        var id = this.references.length + 1;
        replacement = '[' + content + '][' + id + ']';
        reference = '[' + id + ']: ' + href + title;
    }

    this.references.push(reference);
    return replacement
  },

  references: [],

  append: function (options) {
    var references = '';
    if (this.references.length) {
      references = '\n\n' + this.references.join('\n') + '\n\n';
      this.references = []; // Reset references
    }
    return references
  }
};

converters.emphasis = {
  filter: ['em', 'i'],

  replacement: function (content, node, options) {
    return options.emDelimiter + content + options.emDelimiter
  }
};

converters.strong = {
  filter: ['strong', 'b'],

  replacement: function (content, node, options) {
    return options.strongDelimiter + content + options.strongDelimiter
  }
};

converters.code = {
  filter: function (node) {
    var hasSiblings = node.previousSibling || node.nextSibling;
    var isCodeBlock = node.parentNode.nodeName === 'PRE' && !hasSiblings;

    return node.nodeName === 'CODE' && !isCodeBlock
  },

  replacement: function (content) {
    return '`' + content + '`'
  }
};

converters.image = {
  filter: 'img',

  replacement: function (content, node) {
    var alt = node.alt || '';
    var src = node.getAttribute('src') || '';
    var title = node.title || '';
    var titlePart = title ? ' "' + title + '"' : '';
    return src ? '![' + alt + ']' + '(' + src + titlePart + ')' : ''
  }
};

/**
 * This file automatically generated from `pre-publish.js`.
 * Do not manually edit.
 */

var index = {
  "area": true,
  "base": true,
  "br": true,
  "col": true,
  "embed": true,
  "hr": true,
  "img": true,
  "input": true,
  "keygen": true,
  "link": true,
  "menuitem": true,
  "meta": true,
  "param": true,
  "source": true,
  "track": true,
  "wbr": true
};

/**
 * This file automatically generated from `build.js`.
 * Do not manually edit.
 */

var index$2 = [
  "address",
  "article",
  "aside",
  "audio",
  "blockquote",
  "canvas",
  "dd",
  "div",
  "dl",
  "fieldset",
  "figcaption",
  "figure",
  "footer",
  "form",
  "h1",
  "h2",
  "h3",
  "h4",
  "h5",
  "h6",
  "header",
  "hgroup",
  "hr",
  "main",
  "nav",
  "noscript",
  "ol",
  "output",
  "p",
  "pre",
  "section",
  "table",
  "tfoot",
  "ul",
  "video"
];

var voidElements = index;
Object.keys(voidElements).forEach(function (name) {
  voidElements[name.toUpperCase()] = 1;
});

var blockElements = {};
index$2.forEach(function (name) {
  blockElements[name.toUpperCase()] = 1;
});

/**
 * isBlockElem(node) determines if the given node is a block element.
 *
 * @param {Node} node
 * @return {Boolean}
 */
function isBlockElem(node) {
  return !!(node && blockElements[node.nodeName]);
}

/**
 * isVoid(node) determines if the given node is a void element.
 *
 * @param {Node} node
 * @return {Boolean}
 */
function isVoid(node) {
  return !!(node && voidElements[node.nodeName]);
}

/**
 * whitespace(elem [, isBlock]) removes extraneous whitespace from an
 * the given element. The function isBlock may optionally be passed in
 * to determine whether or not an element is a block element; if none
 * is provided, defaults to using the list of block elements provided
 * by the `block-elements` module.
 *
 * @param {Node} elem
 * @param {Function} blockTest
 */
function collapseWhitespace(elem, isBlock) {
  if (!elem.firstChild || elem.nodeName === 'PRE') return;

  if (typeof isBlock !== 'function') {
    isBlock = isBlockElem;
  }

  var prevText = null;
  var prevVoid = false;

  var prev = null;
  var node = next(prev, elem);

  while (node !== elem) {
    if (node.nodeType === 3) {
      // Node.TEXT_NODE
      var text = node.data.replace(/[ \r\n\t]+/g, ' ');

      if ((!prevText || / $/.test(prevText.data)) && !prevVoid && text[0] === ' ') {
        text = text.substr(1);
      }

      // `text` might be empty at this point.
      if (!text) {
        node = remove(node);
        continue;
      }

      node.data = text;
      prevText = node;
    } else if (node.nodeType === 1) {
      // Node.ELEMENT_NODE
      if (isBlock(node) || node.nodeName === 'BR') {
        if (prevText) {
          prevText.data = prevText.data.replace(/ $/, '');
        }

        prevText = null;
        prevVoid = false;
      } else if (isVoid(node)) {
        // Avoid trimming space around non-block, non-BR void elements.
        prevText = null;
        prevVoid = true;
      }
    } else {
      node = remove(node);
      continue;
    }

    var nextNode = next(prev, node);
    prev = node;
    node = nextNode;
  }

  if (prevText) {
    prevText.data = prevText.data.replace(/ $/, '');
    if (!prevText.data) {
      remove(prevText);
    }
  }
}

/**
 * remove(node) removes the given node from the DOM and returns the
 * next node in the sequence.
 *
 * @param {Node} node
 * @return {Node} node
 */
function remove(node) {
  var next = node.nextSibling || node.parentNode;

  node.parentNode.removeChild(node);

  return next;
}

/**
 * next(prev, current) returns the next node in the sequence, given the
 * current and previous nodes.
 *
 * @param {Node} prev
 * @param {Node} current
 * @return {Node}
 */
function next(prev, current) {
  if (prev && prev.parentNode === current || current.nodeName === 'PRE') {
    return current.nextSibling || current.parentNode;
  }

  return current.firstChild || current.nextSibling || current.parentNode;
}

var whitespace = collapseWhitespace;

/*
 * Set up window for Node.js
 */

var root = (typeof window !== 'undefined' ? window : {});

/*
 * Parsing HTML strings
 */

function canParseHTMLNatively () {
  var Parser = root.DOMParser;
  var canParse = false;

  // Adapted from https://gist.github.com/1129031
  // Firefox/Opera/IE throw errors on unsupported types
  try {
    // WebKit returns null on unsupported types
    if (new Parser().parseFromString('', 'text/html')) {
      canParse = true;
    }
  } catch (e) {}

  return canParse
}

function createHTMLParser () {
  var Parser = function () {};

  // For Node.js environments
  if (typeof document === 'undefined') {
    var jsdom = require('jsdom');
    Parser.prototype.parseFromString = function (string) {
      return jsdom.jsdom(string, {
        features: {
          FetchExternalResources: [],
          ProcessExternalResources: false
        }
      })
    };
  } else {
    if (!shouldUseActiveX()) {
      Parser.prototype.parseFromString = function (string) {
        var doc = document.implementation.createHTMLDocument('');
        doc.open();
        doc.write(string);
        doc.close();
        return doc
      };
    } else {
      Parser.prototype.parseFromString = function (string) {
        var doc = new window.ActiveXObject('htmlfile');
        doc.designMode = 'on'; // disable on-page scripts
        doc.open();
        doc.write(string);
        doc.close();
        return doc
      };
    }
  }
  return Parser
}

function shouldUseActiveX () {
  var useActiveX = false;
  try {
    document.implementation.createHTMLDocument('').open();
  } catch (e) {
    if (window.ActiveXObject) useActiveX = true;
  }
  return useActiveX
}

var HTMLParser = canParseHTMLNatively() ? root.DOMParser : createHTMLParser();

function RootNode (input) {
  var root;
  if (typeof input === 'string') {
    root = htmlParser().parseFromString(input, 'text/html').body;
  } else {
    root = input.cloneNode(true);
  }
  whitespace(root, isBlock);

  return root
}

var _htmlParser;
function htmlParser () {
  _htmlParser = _htmlParser || new HTMLParser();
  return _htmlParser
}

function Node (node) {
  node.isBlock = isBlock(node);
  node.isVoid = isVoid$1(node);
  node.isBlank = isBlank(node);
  node.flankingWhitespace = flankingWhitespace(node);
  return node
}

function isVoid$1 (node) {
  return [
    'area', 'base', 'br', 'col', 'command', 'embed', 'hr', 'img', 'input',
    'keygen', 'link', 'meta', 'param', 'source', 'track', 'wbr'
  ].indexOf(node.nodeName.toLowerCase()) !== -1
}

function isBlank (node) {
  return (
    !isVoid$1(node) &&
    !/A|TH|TD/.test(node.nodeName) &&
    /^\s*$/i.test(node.textContent)
  )
}

function flankingWhitespace (node) {
  var leading = '';
  var trailing = '';

  if (!isBlock(node)) {
    var hasLeading = /^[ \r\n\t]/.test(node.textContent);
    var hasTrailing = /[ \r\n\t]$/.test(node.textContent);

    if (hasLeading && !isFlankedByWhitespace('left', node)) {
      leading = ' ';
    }
    if (hasTrailing && !isFlankedByWhitespace('right', node)) {
      trailing = ' ';
    }
  }

  return { leading: leading, trailing: trailing }
}

function isFlankedByWhitespace (side, node) {
  var sibling;
  var regExp;
  var isFlanked;

  if (side === 'left') {
    sibling = node.previousSibling;
    regExp = / $/;
  } else {
    sibling = node.nextSibling;
    regExp = /^ /;
  }

  if (sibling) {
    if (sibling.nodeType === 3) {
      isFlanked = regExp.test(sibling.nodeValue);
    } else if (sibling.nodeType === 1 && !isBlock(sibling)) {
      isFlanked = regExp.test(sibling.textContent);
    }
  }
  return isFlanked
}

var reduce = Array.prototype.reduce;
var leadingNewLinesRegExp = /^\n*/;
var trailingNewLinesRegExp = /\n*$/;

function TurndownService (options) {
  var defaults = {
    converters: converters,
    headingStyle: 'setext',
    hr: '* * *',
    bulletListMarker: '*',
    codeBlockStyle: 'indented',
    fence: '```',
    emDelimiter: '_',
    strongDelimiter: '**',
    linkStyle: 'inlined',
    linkReferenceStyle: 'full',
    blankConverter: {
      replacement: function (content, node) {
        return node.isBlock ? '\n\n' : ''
      }
    },
    defaultConverter: {
      replacement: function (content, node) {
        return node.isBlock ? '\n\n' + content + '\n\n' : content
      }
    },
    keepConverter: {
      filter: function (node) {
        switch (node.nodeName) {
          case 'TABLE':
            return true
          case 'PRE':
            return node.firstChild.nodeName !== 'CODE'
          default:
            return false
        }
      },
      replacement: function (content, node) {
        return node.isBlock ? '\n\n' + node.outerHTML + '\n\n' : node.outerHTML
      }
    },
    removeConverter: {
      filter: ['head'],
      replacement: function () {
        return ''
      }
    }
  };

  this.options = extend({}, defaults, options);
}

TurndownService.prototype = {
  turndown: function (input) {
    if (!canConvert(input)) {
      throw new TypeError(
        input + ' is not a string, or an element/document/fragment node.'
      )
    }

    if (input === '') return ''

    var root = new RootNode(input);
    return this.postProcess(this.process(root))
  },

  /**
   * Reduces a DOM node down to its Markdown string equivalent
   */

  process: function process (parentNode) {
    var _this = this;
    return reduce.call(parentNode.childNodes, function (output, node) {
      node = new Node(node);

      var replacement;
      if (node.nodeType === 3) {
        replacement = _this.escape(node.nodeValue);
      } else if (node.nodeType === 1) {
        replacement = _this.replacementForNode(node);
      }

      return join(output, replacement)
    }, '')
  },

  /**
   * Escapes Markdown syntax
   */

  escape: function escape (string) {
    return (
      string
        // Escape hr
        .replace(/^([-*_] *){3,}$/gm, function (match, character) {
          return match.split(character).join('\\' + character)
        })

        // Escape ol bullet points
        .replace(/^(\W* {0,3})(\d+)\. /gm, '$1$2\\. ')

        // Escape ul bullet points
        .replace(/^([^\\\w]*)([*+-]) /gm, '$1\\$2 ')

        // Escape blockquote indents
        .replace(/^(\W* {0,3})> /gm, '$1\\> ')

        // Escape em/strong *
        .replace(/\*{1,2}([^\W*]+\W*)+\*{1,2}/g, function (match) {
          return match.replace(/\*/g, '\\*')
        })

        // Escape em/strong _
        .replace(/_{1,2}([^\W_]+\W*)+_{1,2}/g, function (match) {
          return match.replace(/_/g, '\\_')
        })

        // Escape `
        .replace(/`([^\W`]+\W*)+`/g, function (match) {
          return match.replace(/`/g, '\\`')
        })

        // Escape link brackets
        .replace(/\[([^\]]*)\]/g, '\\[$1\\]') // eslint-disable-line no-useless-escape
    )
  },

  /**
   * Converts an element node to its Markdown equivalent
   */

  replacementForNode: function replacementForNode (node) {
    var converter = this.converterForNode(node);
    var content = this.process(node);
    var whitespace = node.flankingWhitespace;
    if (whitespace.leading || whitespace.trailing) content = content.trim();

    return (
      whitespace.leading +
      converter.replacement(content, node, this.options) +
      whitespace.trailing
    )
  },

  /**
   * Finds a converter for a given node
   */

  converterForNode: function converterForNode (node) {
    if (this.filterValue(this.options.keepConverter, node)) {
      return this.options.keepConverter
    }
    if (this.filterValue(this.options.removeConverter, node)) {
      return this.options.removeConverter
    }
    if (node.isBlank) return this.options.blankConverter

    for (var key in this.options.converters) {
      var converter = this.options.converters[key];
      if (this.filterValue(converter, node)) return converter
    }

    return this.options.defaultConverter
  },

  filterValue: function filterValue (converter, node) {
    var filter = converter.filter;
    if (typeof filter === 'string') {
      if (filter === node.nodeName.toLowerCase()) return true
    } else if (Array.isArray(filter)) {
      if (filter.indexOf(node.nodeName.toLowerCase()) > -1) return true
    } else if (typeof filter === 'function') {
      if (filter.call(converter, node, this.options)) return true
    } else {
      throw new TypeError('`filter` needs to be a string, array, or function')
    }
  },

  postProcess: function postProcess (output) {
    for (var key in this.options.converters) {
      var converter = this.options.converters[key];
      if (typeof converter.append === 'function') {
        output = join(output, converter.append(this.options));
      }
    }
    return output.replace(/^[\t\r\n]+/, '').replace(/[\t\r\n\s]+$/, '')
  }
};

function separatingNewlines (output, replacement) {
  var newlines = [
    output.match(trailingNewLinesRegExp)[0],
    replacement.match(leadingNewLinesRegExp)[0]
  ].sort();
  return newlines[newlines.length - 1]
}

function join (string1, string2) {
  var separator = separatingNewlines(string1, string2);

  // Remove trailing/leading newlines and replace with separator
  string1 = string1.replace(trailingNewLinesRegExp, '');
  string2 = string2.replace(leadingNewLinesRegExp, '');

  return string1 + separator + string2
}

/**
 * Determines whether an input can be converted
 */

function canConvert (input) {
  return (
    input != null && (
      typeof input === 'string' ||
      input.nodeType && (
        input.nodeType === 1 || input.nodeType === 9 || input.nodeType === 11
      )
    )
  )
}

export default TurndownService;