marked/lib/marked.esm.js

/**
 * marked - a markdown parser
 * Copyright (c) 2011-2022, Christopher Jeffrey. (MIT Licensed)
 * https://github.com/markedjs/marked
 */

/**
 * DO NOT EDIT THIS FILE
 * The code in this file is generated from files in ./src/
 */

function getDefaults() {
  return {
    baseUrl: null,
    breaks: false,
    extensions: null,
    gfm: true,
    headerIds: true,
    headerPrefix: '',
    highlight: null,
    langPrefix: 'language-',
    mangle: true,
    pedantic: false,
    renderer: null,
    sanitize: false,
    sanitizer: null,
    silent: false,
    smartLists: false,
    smartypants: false,
    tokenizer: null,
    walkTokens: null,
    xhtml: false
  };
}

let defaults = getDefaults();

function changeDefaults(newDefaults) {
  defaults = newDefaults;
}

/**
 * Helpers
 */
const escapeTest = /[&<>"']/;
const escapeReplace = /[&<>"']/g;
const escapeTestNoEncode = /[<>"']|&(?!#?\w+;)/;
const escapeReplaceNoEncode = /[<>"']|&(?!#?\w+;)/g;
const escapeReplacements = {
  '&': '&amp;',
  '<': '&lt;',
  '>': '&gt;',
  '"': '&quot;',
  "'": '&#39;'
};
const getEscapeReplacement = (ch) => escapeReplacements[ch];
function escape(html, encode) {
  if (encode) {
    if (escapeTest.test(html)) {
      return html.replace(escapeReplace, getEscapeReplacement);
    }
  } else {
    if (escapeTestNoEncode.test(html)) {
      return html.replace(escapeReplaceNoEncode, getEscapeReplacement);
    }
  }

  return html;
}

const unescapeTest = /&(#(?:\d+)|(?:#x[0-9A-Fa-f]+)|(?:\w+));?/ig;

/**
 * @param {string} html
 */
function unescape(html) {
  // explicitly match decimal, hex, and named HTML entities
  return html.replace(unescapeTest, (_, n) => {
    n = n.toLowerCase();
    if (n === 'colon') return ':';
    if (n.charAt(0) === '#') {
      return n.charAt(1) === 'x'
        ? String.fromCharCode(parseInt(n.substring(2), 16))
        : String.fromCharCode(+n.substring(1));
    }
    return '';
  });
}

const caret = /(^|[^\[])\^/g;

/**
 * @param {string | RegExp} regex
 * @param {string} opt
 */
function edit(regex, opt) {
  regex = typeof regex === 'string' ? regex : regex.source;
  opt = opt || '';
  const obj = {
    replace: (name, val) => {
      val = val.source || val;
      val = val.replace(caret, '$1');
      regex = regex.replace(name, val);
      return obj;
    },
    getRegex: () => {
      return new RegExp(regex, opt);
    }
  };
  return obj;
}

const nonWordAndColonTest = /[^\w:]/g;
const originIndependentUrl = /^$|^[a-z][a-z0-9+.-]*:|^[?#]/i;

/**
 * @param {boolean} sanitize
 * @param {string} base
 * @param {string} href
 */
function cleanUrl(sanitize, base, href) {
  if (sanitize) {
    let prot;
    try {
      prot = decodeURIComponent(unescape(href))
        .replace(nonWordAndColonTest, '')
        .toLowerCase();
    } catch (e) {
      return null;
    }
    if (prot.indexOf('javascript:') === 0 || prot.indexOf('vbscript:') === 0 || prot.indexOf('data:') === 0) {
      return null;
    }
  }
  if (base && !originIndependentUrl.test(href)) {
    href = resolveUrl(base, href);
  }
  try {
    href = encodeURI(href).replace(/%25/g, '%');
  } catch (e) {
    return null;
  }
  return href;
}

const baseUrls = {};
const justDomain = /^[^:]+:\/*[^/]*$/;
const protocol = /^([^:]+:)[\s\S]*$/;
const domain = /^([^:]+:\/*[^/]*)[\s\S]*$/;

/**
 * @param {string} base
 * @param {string} href
 */
function resolveUrl(base, href) {
  if (!baseUrls[' ' + base]) {
    // we can ignore everything in base after the last slash of its path component,
    // but we might need to add _that_
    // https://tools.ietf.org/html/rfc3986#section-3
    if (justDomain.test(base)) {
      baseUrls[' ' + base] = base + '/';
    } else {
      baseUrls[' ' + base] = rtrim(base, '/', true);
    }
  }
  base = baseUrls[' ' + base];
  const relativeBase = base.indexOf(':') === -1;

  if (href.substring(0, 2) === '//') {
    if (relativeBase) {
      return href;
    }
    return base.replace(protocol, '$1') + href;
  } else if (href.charAt(0) === '/') {
    if (relativeBase) {
      return href;
    }
    return base.replace(domain, '$1') + href;
  } else {
    return base + href;
  }
}

const noopTest = { exec: function noopTest() {} };

function merge(obj) {
  let i = 1,
    target,
    key;

  for (; i < arguments.length; i++) {
    target = arguments[i];
    for (key in target) {
      if (Object.prototype.hasOwnProperty.call(target, key)) {
        obj[key] = target[key];
      }
    }
  }

  return obj;
}

function splitCells(tableRow, count) {
  // ensure that every cell-delimiting pipe has a space
  // before it to distinguish it from an escaped pipe
  const row = tableRow.replace(/\|/g, (match, offset, str) => {
      let escaped = false,
        curr = offset;
      while (--curr >= 0 && str[curr] === '\\') escaped = !escaped;
      if (escaped) {
        // odd number of slashes means | is escaped
        // so we leave it alone
        return '|';
      } else {
        // add space before unescaped |
        return ' |';
      }
    }),
    cells = row.split(/ \|/);
  let i = 0;

  // First/last cell in a row cannot be empty if it has no leading/trailing pipe
  if (!cells[0].trim()) { cells.shift(); }
  if (cells.length > 0 && !cells[cells.length - 1].trim()) { cells.pop(); }

  if (cells.length > count) {
    cells.splice(count);
  } else {
    while (cells.length < count) cells.push('');
  }

  for (; i < cells.length; i++) {
    // leading or trailing whitespace is ignored per the gfm spec
    cells[i] = cells[i].trim().replace(/\\\|/g, '|');
  }
  return cells;
}

/**
 * Remove trailing 'c's. Equivalent to str.replace(/c*$/, '').
 * /c*$/ is vulnerable to REDOS.
 *
 * @param {string} str
 * @param {string} c
 * @param {boolean} invert Remove suffix of non-c chars instead. Default falsey.
 */
function rtrim(str, c, invert) {
  const l = str.length;
  if (l === 0) {
    return '';
  }

  // Length of suffix matching the invert condition.
  let suffLen = 0;

  // Step left until we fail to match the invert condition.
  while (suffLen < l) {
    const currChar = str.charAt(l - suffLen - 1);
    if (currChar === c && !invert) {
      suffLen++;
    } else if (currChar !== c && invert) {
      suffLen++;
    } else {
      break;
    }
  }

  return str.slice(0, l - suffLen);
}

function findClosingBracket(str, b) {
  if (str.indexOf(b[1]) === -1) {
    return -1;
  }
  const l = str.length;
  let level = 0,
    i = 0;
  for (; i < l; i++) {
    if (str[i] === '\\') {
      i++;
    } else if (str[i] === b[0]) {
      level++;
    } else if (str[i] === b[1]) {
      level--;
      if (level < 0) {
        return i;
      }
    }
  }
  return -1;
}

function checkSanitizeDeprecation(opt) {
  if (opt && opt.sanitize && !opt.silent) {
    console.warn('marked(): sanitize and sanitizer parameters are deprecated since version 0.7.0, should not be used and will be removed in the future. Read more here: https://marked.js.org/#/USING_ADVANCED.md#options');
  }
}

// copied from https://stackoverflow.com/a/5450113/806777
/**
 * @param {string} pattern
 * @param {number} count
 */
function repeatString(pattern, count) {
  if (count < 1) {
    return '';
  }
  let result = '';
  while (count > 1) {
    if (count & 1) {
      result += pattern;
    }
    count >>= 1;
    pattern += pattern;
  }
  return result + pattern;
}

function outputLink(cap, link, raw, lexer) {
  const href = link.href;
  const title = link.title ? escape(link.title) : null;
  const text = cap[1].replace(/\\([\[\]])/g, '$1');

  if (cap[0].charAt(0) !== '!') {
    lexer.state.inLink = true;
    const token = {
      type: 'link',
      raw,
      href,
      title,
      text,
      tokens: lexer.inlineTokens(text, [])
    };
    lexer.state.inLink = false;
    return token;
  }
  return {
    type: 'image',
    raw,
    href,
    title,
    text: escape(text)
  };
}

function indentCodeCompensation(raw, text) {
  const matchIndentToCode = raw.match(/^(\s+)(?:```)/);

  if (matchIndentToCode === null) {
    return text;
  }

  const indentToCode = matchIndentToCode[1];

  return text
    .split('\n')
    .map(node => {
      const matchIndentInNode = node.match(/^\s+/);
      if (matchIndentInNode === null) {
        return node;
      }

      const [indentInNode] = matchIndentInNode;

      if (indentInNode.length >= indentToCode.length) {
        return node.slice(indentToCode.length);
      }

      return node;
    })
    .join('\n');
}

/**
 * Tokenizer
 */
class Tokenizer {
  constructor(options) {
    this.options = options || defaults;
  }

  space(src) {
    const cap = this.rules.block.newline.exec(src);
    if (cap && cap[0].length > 0) {
      return {
        type: 'space',
        raw: cap[0]
      };
    }
  }

  code(src) {
    const cap = this.rules.block.code.exec(src);
    if (cap) {
      const text = cap[0].replace(/^ {1,4}/gm, '');
      return {
        type: 'code',
        raw: cap[0],
        codeBlockStyle: 'indented',
        text: !this.options.pedantic
          ? rtrim(text, '\n')
          : text
      };
    }
  }

  fences(src) {
    const cap = this.rules.block.fences.exec(src);
    if (cap) {
      const raw = cap[0];
      const text = indentCodeCompensation(raw, cap[3] || '');

      return {
        type: 'code',
        raw,
        lang: cap[2] ? cap[2].trim() : cap[2],
        text
      };
    }
  }

  heading(src) {
    const cap = this.rules.block.heading.exec(src);
    if (cap) {
      let text = cap[2].trim();

      // remove trailing #s
      if (/#$/.test(text)) {
        const trimmed = rtrim(text, '#');
        if (this.options.pedantic) {
          text = trimmed.trim();
        } else if (!trimmed || / $/.test(trimmed)) {
          // CommonMark requires space before trailing #s
          text = trimmed.trim();
        }
      }

      const token = {
        type: 'heading',
        raw: cap[0],
        depth: cap[1].length,
        text,
        tokens: []
      };
      this.lexer.inline(token.text, token.tokens);
      return token;
    }
  }

  hr(src) {
    const cap = this.rules.block.hr.exec(src);
    if (cap) {
      return {
        type: 'hr',
        raw: cap[0]
      };
    }
  }

  blockquote(src) {
    const cap = this.rules.block.blockquote.exec(src);
    if (cap) {
      const text = cap[0].replace(/^ *>[ \t]?/gm, '');

      return {
        type: 'blockquote',
        raw: cap[0],
        tokens: this.lexer.blockTokens(text, []),
        text
      };
    }
  }

  list(src) {
    let cap = this.rules.block.list.exec(src);
    if (cap) {
      let raw, istask, ischecked, indent, i, blankLine, endsWithBlankLine,
        line, nextLine, rawLine, itemContents, endEarly;

      let bull = cap[1].trim();
      const isordered = bull.length > 1;

      const list = {
        type: 'list',
        raw: '',
        ordered: isordered,
        start: isordered ? +bull.slice(0, -1) : '',
        loose: false,
        items: []
      };

      bull = isordered ? `\\d{1,9}\\${bull.slice(-1)}` : `\\${bull}`;

      if (this.options.pedantic) {
        bull = isordered ? bull : '[*+-]';
      }

      // Get next list item
      const itemRegex = new RegExp(`^( {0,3}${bull})((?:[\t ][^\\n]*)?(?:\\n|$))`);

      // Check if current bullet point can start a new List Item
      while (src) {
        endEarly = false;
        if (!(cap = itemRegex.exec(src))) {
          break;
        }

        if (this.rules.block.hr.test(src)) { // End list if bullet was actually HR (possibly move into itemRegex?)
          break;
        }

        raw = cap[0];
        src = src.substring(raw.length);

        line = cap[2].split('\n', 1)[0];
        nextLine = src.split('\n', 1)[0];

        if (this.options.pedantic) {
          indent = 2;
          itemContents = line.trimLeft();
        } else {
          indent = cap[2].search(/[^ ]/); // Find first non-space char
          indent = indent > 4 ? 1 : indent; // Treat indented code blocks (> 4 spaces) as having only 1 indent
          itemContents = line.slice(indent);
          indent += cap[1].length;
        }

        blankLine = false;

        if (!line && /^ *$/.test(nextLine)) { // Items begin with at most one blank line
          raw += nextLine + '\n';
          src = src.substring(nextLine.length + 1);
          endEarly = true;
        }

        if (!endEarly) {
          const nextBulletRegex = new RegExp(`^ {0,${Math.min(3, indent - 1)}}(?:[*+-]|\\d{1,9}[.)])((?: [^\\n]*)?(?:\\n|$))`);
          const hrRegex = new RegExp(`^ {0,${Math.min(3, indent - 1)}}((?:- *){3,}|(?:_ *){3,}|(?:\\* *){3,})(?:\\n+|$)`);
          const fencesBeginRegex = new RegExp(`^ {0,${Math.min(3, indent - 1)}}(?:\`\`\`|~~~)`);
          const headingBeginRegex = new RegExp(`^ {0,${Math.min(3, indent - 1)}}#`);

          // Check if following lines should be included in List Item
          while (src) {
            rawLine = src.split('\n', 1)[0];
            line = rawLine;

            // Re-align to follow commonmark nesting rules
            if (this.options.pedantic) {
              line = line.replace(/^ {1,4}(?=( {4})*[^ ])/g, '  ');
            }

            // End list item if found code fences
            if (fencesBeginRegex.test(line)) {
              break;
            }

            // End list item if found start of new heading
            if (headingBeginRegex.test(line)) {
              break;
            }

            // End list item if found start of new bullet
            if (nextBulletRegex.test(line)) {
              break;
            }

            // Horizontal rule found
            if (hrRegex.test(src)) {
              break;
            }

            if (line.search(/[^ ]/) >= indent || !line.trim()) { // Dedent if possible
              itemContents += '\n' + line.slice(indent);
            } else if (!blankLine) { // Until blank line, item doesn't need indentation
              itemContents += '\n' + line;
            } else { // Otherwise, improper indentation ends this item
              break;
            }

            if (!blankLine && !line.trim()) { // Check if current line is blank
              blankLine = true;
            }

            raw += rawLine + '\n';
            src = src.substring(rawLine.length + 1);
          }
        }

        if (!list.loose) {
          // If the previous item ended with a blank line, the list is loose
          if (endsWithBlankLine) {
            list.loose = true;
          } else if (/\n *\n *$/.test(raw)) {
            endsWithBlankLine = true;
          }
        }

        // Check for task list items
        if (this.options.gfm) {
          istask = /^\[[ xX]\] /.exec(itemContents);
          if (istask) {
            ischecked = istask[0] !== '[ ] ';
            itemContents = itemContents.replace(/^\[[ xX]\] +/, '');
          }
        }

        list.items.push({
          type: 'list_item',
          raw,
          task: !!istask,
          checked: ischecked,
          loose: false,
          text: itemContents
        });

        list.raw += raw;
      }

      // Do not consume newlines at end of final item. Alternatively, make itemRegex *start* with any newlines to simplify/speed up endsWithBlankLine logic
      list.items[list.items.length - 1].raw = raw.trimRight();
      list.items[list.items.length - 1].text = itemContents.trimRight();
      list.raw = list.raw.trimRight();

      const l = list.items.length;

      // Item child tokens handled here at end because we needed to have the final item to trim it first
      for (i = 0; i < l; i++) {
        this.lexer.state.top = false;
        list.items[i].tokens = this.lexer.blockTokens(list.items[i].text, []);
        const spacers = list.items[i].tokens.filter(t => t.type === 'space');
        const hasMultipleLineBreaks = spacers.every(t => {
          const chars = t.raw.split('');
          let lineBreaks = 0;
          for (const char of chars) {
            if (char === '\n') {
              lineBreaks += 1;
            }
            if (lineBreaks > 1) {
              return true;
            }
          }

          return false;
        });

        if (!list.loose && spacers.length && hasMultipleLineBreaks) {
          // Having a single line break doesn't mean a list is loose. A single line break is terminating the last list item
          list.loose = true;
          list.items[i].loose = true;
        }
      }

      return list;
    }
  }

  html(src) {
    const cap = this.rules.block.html.exec(src);
    if (cap) {
      const token = {
        type: 'html',
        raw: cap[0],
        pre: !this.options.sanitizer
          && (cap[1] === 'pre' || cap[1] === 'script' || cap[1] === 'style'),
        text: cap[0]
      };
      if (this.options.sanitize) {
        token.type = 'paragraph';
        token.text = this.options.sanitizer ? this.options.sanitizer(cap[0]) : escape(cap[0]);
        token.tokens = [];
        this.lexer.inline(token.text, token.tokens);
      }
      return token;
    }
  }

  def(src) {
    const cap = this.rules.block.def.exec(src);
    if (cap) {
      if (cap[3]) cap[3] = cap[3].substring(1, cap[3].length - 1);
      const tag = cap[1].toLowerCase().replace(/\s+/g, ' ');
      return {
        type: 'def',
        tag,
        raw: cap[0],
        href: cap[2],
        title: cap[3]
      };
    }
  }

  table(src) {
    const cap = this.rules.block.table.exec(src);
    if (cap) {
      const item = {
        type: 'table',
        header: splitCells(cap[1]).map(c => { return { text: c }; }),
        align: cap[2].replace(/^ *|\| *$/g, '').split(/ *\| */),
        rows: cap[3] && cap[3].trim() ? cap[3].replace(/\n[ \t]*$/, '').split('\n') : []
      };

      if (item.header.length === item.align.length) {
        item.raw = cap[0];

        let l = item.align.length;
        let i, j, k, row;
        for (i = 0; i < l; i++) {
          if (/^ *-+: *$/.test(item.align[i])) {
            item.align[i] = 'right';
          } else if (/^ *:-+: *$/.test(item.align[i])) {
            item.align[i] = 'center';
          } else if (/^ *:-+ *$/.test(item.align[i])) {
            item.align[i] = 'left';
          } else {
            item.align[i] = null;
          }
        }

        l = item.rows.length;
        for (i = 0; i < l; i++) {
          item.rows[i] = splitCells(item.rows[i], item.header.length).map(c => { return { text: c }; });
        }

        // parse child tokens inside headers and cells

        // header child tokens
        l = item.header.length;
        for (j = 0; j < l; j++) {
          item.header[j].tokens = [];
          this.lexer.inline(item.header[j].text, item.header[j].tokens);
        }

        // cell child tokens
        l = item.rows.length;
        for (j = 0; j < l; j++) {
          row = item.rows[j];
          for (k = 0; k < row.length; k++) {
            row[k].tokens = [];
            this.lexer.inline(row[k].text, row[k].tokens);
          }
        }

        return item;
      }
    }
  }

  lheading(src) {
    const cap = this.rules.block.lheading.exec(src);
    if (cap) {
      const token = {
        type: 'heading',
        raw: cap[0],
        depth: cap[2].charAt(0) === '=' ? 1 : 2,
        text: cap[1],
        tokens: []
      };
      this.lexer.inline(token.text, token.tokens);
      return token;
    }
  }

  paragraph(src) {
    const cap = this.rules.block.paragraph.exec(src);
    if (cap) {
      const token = {
        type: 'paragraph',
        raw: cap[0],
        text: cap[1].charAt(cap[1].length - 1) === '\n'
          ? cap[1].slice(0, -1)
          : cap[1],
        tokens: []
      };
      this.lexer.inline(token.text, token.tokens);
      return token;
    }
  }

  text(src) {
    const cap = this.rules.block.text.exec(src);
    if (cap) {
      const token = {
        type: 'text',
        raw: cap[0],
        text: cap[0],
        tokens: []
      };
      this.lexer.inline(token.text, token.tokens);
      return token;
    }
  }

  escape(src) {
    const cap = this.rules.inline.escape.exec(src);
    if (cap) {
      return {
        type: 'escape',
        raw: cap[0],
        text: escape(cap[1])
      };
    }
  }

  tag(src) {
    const cap = this.rules.inline.tag.exec(src);
    if (cap) {
      if (!this.lexer.state.inLink && /^<a /i.test(cap[0])) {
        this.lexer.state.inLink = true;
      } else if (this.lexer.state.inLink && /^<\/a>/i.test(cap[0])) {
        this.lexer.state.inLink = false;
      }
      if (!this.lexer.state.inRawBlock && /^<(pre|code|kbd|script)(\s|>)/i.test(cap[0])) {
        this.lexer.state.inRawBlock = true;
      } else if (this.lexer.state.inRawBlock && /^<\/(pre|code|kbd|script)(\s|>)/i.test(cap[0])) {
        this.lexer.state.inRawBlock = false;
      }

      return {
        type: this.options.sanitize
          ? 'text'
          : 'html',
        raw: cap[0],
        inLink: this.lexer.state.inLink,
        inRawBlock: this.lexer.state.inRawBlock,
        text: this.options.sanitize
          ? (this.options.sanitizer
            ? this.options.sanitizer(cap[0])
            : escape(cap[0]))
          : cap[0]
      };
    }
  }

  link(src) {
    const cap = this.rules.inline.link.exec(src);
    if (cap) {
      const trimmedUrl = cap[2].trim();
      if (!this.options.pedantic && /^</.test(trimmedUrl)) {
        // commonmark requires matching angle brackets
        if (!(/>$/.test(trimmedUrl))) {
          return;
        }

        // ending angle bracket cannot be escaped
        const rtrimSlash = rtrim(trimmedUrl.slice(0, -1), '\\');
        if ((trimmedUrl.length - rtrimSlash.length) % 2 === 0) {
          return;
        }
      } else {
        // find closing parenthesis
        const lastParenIndex = findClosingBracket(cap[2], '()');
        if (lastParenIndex > -1) {
          const start = cap[0].indexOf('!') === 0 ? 5 : 4;
          const linkLen = start + cap[1].length + lastParenIndex;
          cap[2] = cap[2].substring(0, lastParenIndex);
          cap[0] = cap[0].substring(0, linkLen).trim();
          cap[3] = '';
        }
      }
      let href = cap[2];
      let title = '';
      if (this.options.pedantic) {
        // split pedantic href and title
        const link = /^([^'"]*[^\s])\s+(['"])(.*)\2/.exec(href);

        if (link) {
          href = link[1];
          title = link[3];
        }
      } else {
        title = cap[3] ? cap[3].slice(1, -1) : '';
      }

      href = href.trim();
      if (/^</.test(href)) {
        if (this.options.pedantic && !(/>$/.test(trimmedUrl))) {
          // pedantic allows starting angle bracket without ending angle bracket
          href = href.slice(1);
        } else {
          href = href.slice(1, -1);
        }
      }
      return outputLink(cap, {
        href: href ? href.replace(this.rules.inline._escapes, '$1') : href,
        title: title ? title.replace(this.rules.inline._escapes, '$1') : title
      }, cap[0], this.lexer);
    }
  }

  reflink(src, links) {
    let cap;
    if ((cap = this.rules.inline.reflink.exec(src))
        || (cap = this.rules.inline.nolink.exec(src))) {
      let link = (cap[2] || cap[1]).replace(/\s+/g, ' ');
      link = links[link.toLowerCase()];
      if (!link || !link.href) {
        const text = cap[0].charAt(0);
        return {
          type: 'text',
          raw: text,
          text
        };
      }
      return outputLink(cap, link, cap[0], this.lexer);
    }
  }

  emStrong(src, maskedSrc, prevChar = '') {
    let match = this.rules.inline.emStrong.lDelim.exec(src);
    if (!match) return;

    // _ can't be between two alphanumerics. \p{L}\p{N} includes non-english alphabet/numbers as well
    if (match[3] && prevChar.match(/[\p{L}\p{N}]/u)) return;

    const nextChar = match[1] || match[2] || '';

    if (!nextChar || (nextChar && (prevChar === '' || this.rules.inline.punctuation.exec(prevChar)))) {
      const lLength = match[0].length - 1;
      let rDelim, rLength, delimTotal = lLength, midDelimTotal = 0;

      const endReg = match[0][0] === '*' ? this.rules.inline.emStrong.rDelimAst : this.rules.inline.emStrong.rDelimUnd;
      endReg.lastIndex = 0;

      // Clip maskedSrc to same section of string as src (move to lexer?)
      maskedSrc = maskedSrc.slice(-1 * src.length + lLength);

      while ((match = endReg.exec(maskedSrc)) != null) {
        rDelim = match[1] || match[2] || match[3] || match[4] || match[5] || match[6];

        if (!rDelim) continue; // skip single * in __abc*abc__

        rLength = rDelim.length;

        if (match[3] || match[4]) { // found another Left Delim
          delimTotal += rLength;
          continue;
        } else if (match[5] || match[6]) { // either Left or Right Delim
          if (lLength % 3 && !((lLength + rLength) % 3)) {
            midDelimTotal += rLength;
            continue; // CommonMark Emphasis Rules 9-10
          }
        }

        delimTotal -= rLength;

        if (delimTotal > 0) continue; // Haven't found enough closing delimiters

        // Remove extra characters. *a*** -> *a*
        rLength = Math.min(rLength, rLength + delimTotal + midDelimTotal);

        // Create `em` if smallest delimiter has odd char count. *a***
        if (Math.min(lLength, rLength) % 2) {
          const text = src.slice(1, lLength + match.index + rLength);
          return {
            type: 'em',
            raw: src.slice(0, lLength + match.index + rLength + 1),
            text,
            tokens: this.lexer.inlineTokens(text, [])
          };
        }

        // Create 'strong' if smallest delimiter has even char count. **a***
        const text = src.slice(2, lLength + match.index + rLength - 1);
        return {
          type: 'strong',
          raw: src.slice(0, lLength + match.index + rLength + 1),
          text,
          tokens: this.lexer.inlineTokens(text, [])
        };
      }
    }
  }

  codespan(src) {
    const cap = this.rules.inline.code.exec(src);
    if (cap) {
      let text = cap[2].replace(/\n/g, ' ');
      const hasNonSpaceChars = /[^ ]/.test(text);
      const hasSpaceCharsOnBothEnds = /^ /.test(text) && / $/.test(text);
      if (hasNonSpaceChars && hasSpaceCharsOnBothEnds) {
        text = text.substring(1, text.length - 1);
      }
      text = escape(text, true);
      return {
        type: 'codespan',
        raw: cap[0],
        text
      };
    }
  }

  br(src) {
    const cap = this.rules.inline.br.exec(src);
    if (cap) {
      return {
        type: 'br',
        raw: cap[0]
      };
    }
  }

  del(src) {
    const cap = this.rules.inline.del.exec(src);
    if (cap) {
      return {
        type: 'del',
        raw: cap[0],
        text: cap[2],
        tokens: this.lexer.inlineTokens(cap[2], [])
      };
    }
  }

  autolink(src, mangle) {
    const cap = this.rules.inline.autolink.exec(src);
    if (cap) {
      let text, href;
      if (cap[2] === '@') {
        text = escape(this.options.mangle ? mangle(cap[1]) : cap[1]);
        href = 'mailto:' + text;
      } else {
        text = escape(cap[1]);
        href = text;
      }

      return {
        type: 'link',
        raw: cap[0],
        text,
        href,
        tokens: [
          {
            type: 'text',
            raw: text,
            text
          }
        ]
      };
    }
  }

  url(src, mangle) {
    let cap;
    if (cap = this.rules.inline.url.exec(src)) {
      let text, href;
      if (cap[2] === '@') {
        text = escape(this.options.mangle ? mangle(cap[0]) : cap[0]);
        href = 'mailto:' + text;
      } else {
        // do extended autolink path validation
        let prevCapZero;
        do {
          prevCapZero = cap[0];
          cap[0] = this.rules.inline._backpedal.exec(cap[0])[0];
        } while (prevCapZero !== cap[0]);
        text = escape(cap[0]);
        if (cap[1] === 'www.') {
          href = 'http://' + text;
        } else {
          href = text;
        }
      }
      return {
        type: 'link',
        raw: cap[0],
        text,
        href,
        tokens: [
          {
            type: 'text',
            raw: text,
            text
          }
        ]
      };
    }
  }

  inlineText(src, smartypants) {
    const cap = this.rules.inline.text.exec(src);
    if (cap) {
      let text;
      if (this.lexer.state.inRawBlock) {
        text = this.options.sanitize ? (this.options.sanitizer ? this.options.sanitizer(cap[0]) : escape(cap[0])) : cap[0];
      } else {
        text = escape(this.options.smartypants ? smartypants(cap[0]) : cap[0]);
      }
      return {
        type: 'text',
        raw: cap[0],
        text
      };
    }
  }
}

/**
 * Block-Level Grammar
 */
const block = {
  newline: /^(?: *(?:\n|$))+/,
  code: /^( {4}[^\n]+(?:\n(?: *(?:\n|$))*)?)+/,
  fences: /^ {0,3}(`{3,}(?=[^`\n]*\n)|~{3,})([^\n]*)\n(?:|([\s\S]*?)\n)(?: {0,3}\1[~`]* *(?=\n|$)|$)/,
  hr: /^ {0,3}((?:-[\t ]*){3,}|(?:_[ \t]*){3,}|(?:\*[ \t]*){3,})(?:\n+|$)/,
  heading: /^ {0,3}(#{1,6})(?=\s|$)(.*)(?:\n+|$)/,
  blockquote: /^( {0,3}> ?(paragraph|[^\n]*)(?:\n|$))+/,
  list: /^( {0,3}bull)([ \t][^\n]+?)?(?:\n|$)/,
  html: '^ {0,3}(?:' // optional indentation
    + '<(script|pre|style|textarea)[\\s>][\\s\\S]*?(?:</\\1>[^\\n]*\\n+|$)' // (1)
    + '|comment[^\\n]*(\\n+|$)' // (2)
    + '|<\\?[\\s\\S]*?(?:\\?>\\n*|$)' // (3)
    + '|<![A-Z][\\s\\S]*?(?:>\\n*|$)' // (4)
    + '|<!\\[CDATA\\[[\\s\\S]*?(?:\\]\\]>\\n*|$)' // (5)
    + '|</?(tag)(?: +|\\n|/?>)[\\s\\S]*?(?:(?:\\n *)+\\n|$)' // (6)
    + '|<(?!script|pre|style|textarea)([a-z][\\w-]*)(?:attribute)*? */?>(?=[ \\t]*(?:\\n|$))[\\s\\S]*?(?:(?:\\n *)+\\n|$)' // (7) open tag
    + '|</(?!script|pre|style|textarea)[a-z][\\w-]*\\s*>(?=[ \\t]*(?:\\n|$))[\\s\\S]*?(?:(?:\\n *)+\\n|$)' // (7) closing tag
    + ')',
  def: /^ {0,3}\[(label)\]: *(?:\n *)?<?([^\s>]+)>?(?:(?: +(?:\n *)?| *\n *)(title))? *(?:\n+|$)/,
  table: noopTest,
  lheading: /^([^\n]+)\n {0,3}(=+|-+) *(?:\n+|$)/,
  // regex template, placeholders will be replaced according to different paragraph
  // interruption rules of commonmark and the original markdown spec:
  _paragraph: /^([^\n]+(?:\n(?!hr|heading|lheading|blockquote|fences|list|html|table| +\n)[^\n]+)*)/,
  text: /^[^\n]+/
};

block._label = /(?!\s*\])(?:\\.|[^\[\]\\])+/;
block._title = /(?:"(?:\\"?|[^"\\])*"|'[^'\n]*(?:\n[^'\n]+)*\n?'|\([^()]*\))/;
block.def = edit(block.def)
  .replace('label', block._label)
  .replace('title', block._title)
  .getRegex();

block.bullet = /(?:[*+-]|\d{1,9}[.)])/;
block.listItemStart = edit(/^( *)(bull) */)
  .replace('bull', block.bullet)
  .getRegex();

block.list = edit(block.list)
  .replace(/bull/g, block.bullet)
  .replace('hr', '\\n+(?=\\1?(?:(?:- *){3,}|(?:_ *){3,}|(?:\\* *){3,})(?:\\n+|$))')
  .replace('def', '\\n+(?=' + block.def.source + ')')
  .getRegex();

block._tag = 'address|article|aside|base|basefont|blockquote|body|caption'
  + '|center|col|colgroup|dd|details|dialog|dir|div|dl|dt|fieldset|figcaption'
  + '|figure|footer|form|frame|frameset|h[1-6]|head|header|hr|html|iframe'
  + '|legend|li|link|main|menu|menuitem|meta|nav|noframes|ol|optgroup|option'
  + '|p|param|section|source|summary|table|tbody|td|tfoot|th|thead|title|tr'
  + '|track|ul';
block._comment = /<!--(?!-?>)[\s\S]*?(?:-->|$)/;
block.html = edit(block.html, 'i')
  .replace('comment', block._comment)
  .replace('tag', block._tag)
  .replace('attribute', / +[a-zA-Z:_][\w.:-]*(?: *= *"[^"\n]*"| *= *'[^'\n]*'| *= *[^\s"'=<>`]+)?/)
  .getRegex();

block.paragraph = edit(block._paragraph)
  .replace('hr', block.hr)
  .replace('heading', ' {0,3}#{1,6} ')
  .replace('|lheading', '') // setex headings don't interrupt commonmark paragraphs
  .replace('|table', '')
  .replace('blockquote', ' {0,3}>')
  .replace('fences', ' {0,3}(?:`{3,}(?=[^`\\n]*\\n)|~{3,})[^\\n]*\\n')
  .replace('list', ' {0,3}(?:[*+-]|1[.)]) ') // only lists starting from 1 can interrupt
  .replace('html', '</?(?:tag)(?: +|\\n|/?>)|<(?:script|pre|style|textarea|!--)')
  .replace('tag', block._tag) // pars can be interrupted by type (6) html blocks
  .getRegex();

block.blockquote = edit(block.blockquote)
  .replace('paragraph', block.paragraph)
  .getRegex();

/**
 * Normal Block Grammar
 */

block.normal = merge({}, block);

/**
 * GFM Block Grammar
 */

block.gfm = merge({}, block.normal, {
  table: '^ *([^\\n ].*\\|.*)\\n' // Header
    + ' {0,3}(?:\\| *)?(:?-+:? *(?:\\| *:?-+:? *)*)(?:\\| *)?' // Align
    + '(?:\\n((?:(?! *\\n|hr|heading|blockquote|code|fences|list|html).*(?:\\n|$))*)\\n*|$)' // Cells
});

block.gfm.table = edit(block.gfm.table)
  .replace('hr', block.hr)
  .replace('heading', ' {0,3}#{1,6} ')
  .replace('blockquote', ' {0,3}>')
  .replace('code', ' {4}[^\\n]')
  .replace('fences', ' {0,3}(?:`{3,}(?=[^`\\n]*\\n)|~{3,})[^\\n]*\\n')
  .replace('list', ' {0,3}(?:[*+-]|1[.)]) ') // only lists starting from 1 can interrupt
  .replace('html', '</?(?:tag)(?: +|\\n|/?>)|<(?:script|pre|style|textarea|!--)')
  .replace('tag', block._tag) // tables can be interrupted by type (6) html blocks
  .getRegex();

block.gfm.paragraph = edit(block._paragraph)
  .replace('hr', block.hr)
  .replace('heading', ' {0,3}#{1,6} ')
  .replace('|lheading', '') // setex headings don't interrupt commonmark paragraphs
  .replace('table', block.gfm.table) // interrupt paragraphs with table
  .replace('blockquote', ' {0,3}>')
  .replace('fences', ' {0,3}(?:`{3,}(?=[^`\\n]*\\n)|~{3,})[^\\n]*\\n')
  .replace('list', ' {0,3}(?:[*+-]|1[.)]) ') // only lists starting from 1 can interrupt
  .replace('html', '</?(?:tag)(?: +|\\n|/?>)|<(?:script|pre|style|textarea|!--)')
  .replace('tag', block._tag) // pars can be interrupted by type (6) html blocks
  .getRegex();
/**
 * Pedantic grammar (original John Gruber's loose markdown specification)
 */

block.pedantic = merge({}, block.normal, {
  html: edit(
    '^ *(?:comment *(?:\\n|\\s*$)'
    + '|<(tag)[\\s\\S]+?</\\1> *(?:\\n{2,}|\\s*$)' // closed tag
    + '|<tag(?:"[^"]*"|\'[^\']*\'|\\s[^\'"/>\\s]*)*?/?> *(?:\\n{2,}|\\s*$))')
    .replace('comment', block._comment)
    .replace(/tag/g, '(?!(?:'
      + 'a|em|strong|small|s|cite|q|dfn|abbr|data|time|code|var|samp|kbd|sub'
      + '|sup|i|b|u|mark|ruby|rt|rp|bdi|bdo|span|br|wbr|ins|del|img)'
      + '\\b)\\w+(?!:|[^\\w\\s@]*@)\\b')
    .getRegex(),
  def: /^ *\[([^\]]+)\]: *<?([^\s>]+)>?(?: +(["(][^\n]+[")]))? *(?:\n+|$)/,
  heading: /^(#{1,6})(.*)(?:\n+|$)/,
  fences: noopTest, // fences not supported
  paragraph: edit(block.normal._paragraph)
    .replace('hr', block.hr)
    .replace('heading', ' *#{1,6} *[^\n]')
    .replace('lheading', block.lheading)
    .replace('blockquote', ' {0,3}>')
    .replace('|fences', '')
    .replace('|list', '')
    .replace('|html', '')
    .getRegex()
});

/**
 * Inline-Level Grammar
 */
const inline = {
  escape: /^\\([!"#$%&'()*+,\-./:;<=>?@\[\]\\^_`{|}~])/,
  autolink: /^<(scheme:[^\s\x00-\x1f<>]*|email)>/,
  url: noopTest,
  tag: '^comment'
    + '|^</[a-zA-Z][\\w:-]*\\s*>' // self-closing tag
    + '|^<[a-zA-Z][\\w-]*(?:attribute)*?\\s*/?>' // open tag
    + '|^<\\?[\\s\\S]*?\\?>' // processing instruction, e.g. <?php ?>
    + '|^<![a-zA-Z]+\\s[\\s\\S]*?>' // declaration, e.g. <!DOCTYPE html>
    + '|^<!\\[CDATA\\[[\\s\\S]*?\\]\\]>', // CDATA section
  link: /^!?\[(label)\]\(\s*(href)(?:\s+(title))?\s*\)/,
  reflink: /^!?\[(label)\]\[(ref)\]/,
  nolink: /^!?\[(ref)\](?:\[\])?/,
  reflinkSearch: 'reflink|nolink(?!\\()',
  emStrong: {
    lDelim: /^(?:\*+(?:([punct_])|[^\s*]))|^_+(?:([punct*])|([^\s_]))/,
    //        (1) and (2) can only be a Right Delimiter. (3) and (4) can only be Left.  (5) and (6) can be either Left or Right.
    //          () Skip orphan inside strong  () Consume to delim (1) #***                (2) a***#, a***                   (3) #***a, ***a                 (4) ***#              (5) #***#                 (6) a***a
    rDelimAst: /^[^_*]*?\_\_[^_*]*?\*[^_*]*?(?=\_\_)|[^*]+(?=[^*])|[punct_](\*+)(?=[\s]|$)|[^punct*_\s](\*+)(?=[punct_\s]|$)|[punct_\s](\*+)(?=[^punct*_\s])|[\s](\*+)(?=[punct_])|[punct_](\*+)(?=[punct_])|[^punct*_\s](\*+)(?=[^punct*_\s])/,
    rDelimUnd: /^[^_*]*?\*\*[^_*]*?\_[^_*]*?(?=\*\*)|[^_]+(?=[^_])|[punct*](\_+)(?=[\s]|$)|[^punct*_\s](\_+)(?=[punct*\s]|$)|[punct*\s](\_+)(?=[^punct*_\s])|[\s](\_+)(?=[punct*])|[punct*](\_+)(?=[punct*])/ // ^- Not allowed for _
  },
  code: /^(`+)([^`]|[^`][\s\S]*?[^`])\1(?!`)/,
  br: /^( {2,}|\\)\n(?!\s*$)/,
  del: noopTest,
  text: /^(`+|[^`])(?:(?= {2,}\n)|[\s\S]*?(?:(?=[\\<!\[`*_]|\b_|$)|[^ ](?= {2,}\n)))/,
  punctuation: /^([\spunctuation])/
};

// list of punctuation marks from CommonMark spec
// without * and _ to handle the different emphasis markers * and _
inline._punctuation = '!"#$%&\'()+\\-.,/:;<=>?@\\[\\]`^{|}~';
inline.punctuation = edit(inline.punctuation).replace(/punctuation/g, inline._punctuation).getRegex();

// sequences em should skip over [title](link), `code`, <html>
inline.blockSkip = /\[[^\]]*?\]\([^\)]*?\)|`[^`]*?`|<[^>]*?>/g;
inline.escapedEmSt = /\\\*|\\_/g;

inline._comment = edit(block._comment).replace('(?:-->|$)', '-->').getRegex();

inline.emStrong.lDelim = edit(inline.emStrong.lDelim)
  .replace(/punct/g, inline._punctuation)
  .getRegex();

inline.emStrong.rDelimAst = edit(inline.emStrong.rDelimAst, 'g')
  .replace(/punct/g, inline._punctuation)
  .getRegex();

inline.emStrong.rDelimUnd = edit(inline.emStrong.rDelimUnd, 'g')
  .replace(/punct/g, inline._punctuation)
  .getRegex();

inline._escapes = /\\([!"#$%&'()*+,\-./:;<=>?@\[\]\\^_`{|}~])/g;

inline._scheme = /[a-zA-Z][a-zA-Z0-9+.-]{1,31}/;
inline._email = /[a-zA-Z0-9.!#$%&'*+/=?^_`{|}~-]+(@)[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?(?:\.[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?)+(?![-_])/;
inline.autolink = edit(inline.autolink)
  .replace('scheme', inline._scheme)
  .replace('email', inline._email)
  .getRegex();

inline._attribute = /\s+[a-zA-Z:_][\w.:-]*(?:\s*=\s*"[^"]*"|\s*=\s*'[^']*'|\s*=\s*[^\s"'=<>`]+)?/;

inline.tag = edit(inline.tag)
  .replace('comment', inline._comment)
  .replace('attribute', inline._attribute)
  .getRegex();

inline._label = /(?:\[(?:\\.|[^\[\]\\])*\]|\\.|`[^`]*`|[^\[\]\\`])*?/;
inline._href = /<(?:\\.|[^\n<>\\])+>|[^\s\x00-\x1f]*/;
inline._title = /"(?:\\"?|[^"\\])*"|'(?:\\'?|[^'\\])*'|\((?:\\\)?|[^)\\])*\)/;

inline.link = edit(inline.link)
  .replace('label', inline._label)
  .replace('href', inline._href)
  .replace('title', inline._title)
  .getRegex();

inline.reflink = edit(inline.reflink)
  .replace('label', inline._label)
  .replace('ref', block._label)
  .getRegex();

inline.nolink = edit(inline.nolink)
  .replace('ref', block._label)
  .getRegex();

inline.reflinkSearch = edit(inline.reflinkSearch, 'g')
  .replace('reflink', inline.reflink)
  .replace('nolink', inline.nolink)
  .getRegex();

/**
 * Normal Inline Grammar
 */

inline.normal = merge({}, inline);

/**
 * Pedantic Inline Grammar
 */

inline.pedantic = merge({}, inline.normal, {
  strong: {
    start: /^__|\*\*/,
    middle: /^__(?=\S)([\s\S]*?\S)__(?!_)|^\*\*(?=\S)([\s\S]*?\S)\*\*(?!\*)/,
    endAst: /\*\*(?!\*)/g,
    endUnd: /__(?!_)/g
  },
  em: {
    start: /^_|\*/,
    middle: /^()\*(?=\S)([\s\S]*?\S)\*(?!\*)|^_(?=\S)([\s\S]*?\S)_(?!_)/,
    endAst: /\*(?!\*)/g,
    endUnd: /_(?!_)/g
  },
  link: edit(/^!?\[(label)\]\((.*?)\)/)
    .replace('label', inline._label)
    .getRegex(),
  reflink: edit(/^!?\[(label)\]\s*\[([^\]]*)\]/)
    .replace('label', inline._label)
    .getRegex()
});

/**
 * GFM Inline Grammar
 */

inline.gfm = merge({}, inline.normal, {
  escape: edit(inline.escape).replace('])', '~|])').getRegex(),
  _extended_email: /[A-Za-z0-9._+-]+(@)[a-zA-Z0-9-_]+(?:\.[a-zA-Z0-9-_]*[a-zA-Z0-9])+(?![-_])/,
  url: /^((?:ftp|https?):\/\/|www\.)(?:[a-zA-Z0-9\-]+\.?)+[^\s<]*|^email/,
  _backpedal: /(?:[^?!.,:;*_~()&]+|\([^)]*\)|&(?![a-zA-Z0-9]+;$)|[?!.,:;*_~)]+(?!$))+/,
  del: /^(~~?)(?=[^\s~])([\s\S]*?[^\s~])\1(?=[^~]|$)/,
  text: /^([`~]+|[^`~])(?:(?= {2,}\n)|(?=[a-zA-Z0-9.!#$%&'*+\/=?_`{\|}~-]+@)|[\s\S]*?(?:(?=[\\<!\[`*~_]|\b_|https?:\/\/|ftp:\/\/|www\.|$)|[^ ](?= {2,}\n)|[^a-zA-Z0-9.!#$%&'*+\/=?_`{\|}~-](?=[a-zA-Z0-9.!#$%&'*+\/=?_`{\|}~-]+@)))/
});

inline.gfm.url = edit(inline.gfm.url, 'i')
  .replace('email', inline.gfm._extended_email)
  .getRegex();
/**
 * GFM + Line Breaks Inline Grammar
 */

inline.breaks = merge({}, inline.gfm, {
  br: edit(inline.br).replace('{2,}', '*').getRegex(),
  text: edit(inline.gfm.text)
    .replace('\\b_', '\\b_| {2,}\\n')
    .replace(/\{2,\}/g, '*')
    .getRegex()
});

/**
 * smartypants text replacement
 * @param {string} text
 */
function smartypants(text) {
  return text
    // em-dashes
    .replace(/---/g, '\u2014')
    // en-dashes
    .replace(/--/g, '\u2013')
    // opening singles
    .replace(/(^|[-\u2014/(\[{"\s])'/g, '$1\u2018')
    // closing singles & apostrophes
    .replace(/'/g, '\u2019')
    // opening doubles
    .replace(/(^|[-\u2014/(\[{\u2018\s])"/g, '$1\u201c')
    // closing doubles
    .replace(/"/g, '\u201d')
    // ellipses
    .replace(/\.{3}/g, '\u2026');
}

/**
 * mangle email addresses
 * @param {string} text
 */
function mangle(text) {
  let out = '',
    i,
    ch;

  const l = text.length;
  for (i = 0; i < l; i++) {
    ch = text.charCodeAt(i);
    if (Math.random() > 0.5) {
      ch = 'x' + ch.toString(16);
    }
    out += '&#' + ch + ';';
  }

  return out;
}

/**
 * Block Lexer
 */
class Lexer {
  constructor(options) {
    this.tokens = [];
    this.tokens.links = Object.create(null);
    this.options = options || defaults;
    this.options.tokenizer = this.options.tokenizer || new Tokenizer();
    this.tokenizer = this.options.tokenizer;
    this.tokenizer.options = this.options;
    this.tokenizer.lexer = this;
    this.inlineQueue = [];
    this.state = {
      inLink: false,
      inRawBlock: false,
      top: true
    };

    const rules = {
      block: block.normal,
      inline: inline.normal
    };

    if (this.options.pedantic) {
      rules.block = block.pedantic;
      rules.inline = inline.pedantic;
    } else if (this.options.gfm) {
      rules.block = block.gfm;
      if (this.options.breaks) {
        rules.inline = inline.breaks;
      } else {
        rules.inline = inline.gfm;
      }
    }
    this.tokenizer.rules = rules;
  }

  /**
   * Expose Rules
   */
  static get rules() {
    return {
      block,
      inline
    };
  }

  /**
   * Static Lex Method
   */
  static lex(src, options) {
    const lexer = new Lexer(options);
    return lexer.lex(src);
  }

  /**
   * Static Lex Inline Method
   */
  static lexInline(src, options) {
    const lexer = new Lexer(options);
    return lexer.inlineTokens(src);
  }

  /**
   * Preprocessing
   */
  lex(src) {
    src = src
      .replace(/\r\n|\r/g, '\n');

    this.blockTokens(src, this.tokens);

    let next;
    while (next = this.inlineQueue.shift()) {
      this.inlineTokens(next.src, next.tokens);
    }

    return this.tokens;
  }

  /**
   * Lexing
   */
  blockTokens(src, tokens = []) {
    if (this.options.pedantic) {
      src = src.replace(/\t/g, '    ').replace(/^ +$/gm, '');
    } else {
      src = src.replace(/^( *)(\t+)/gm, (_, leading, tabs) => {
        return leading + '    '.repeat(tabs.length);
      });
    }

    let token, lastToken, cutSrc, lastParagraphClipped;

    while (src) {
      if (this.options.extensions
        && this.options.extensions.block
        && this.options.extensions.block.some((extTokenizer) => {
          if (token = extTokenizer.call({ lexer: this }, src, tokens)) {
            src = src.substring(token.raw.length);
            tokens.push(token);
            return true;
          }
          return false;
        })) {
        continue;
      }

      // newline
      if (token = this.tokenizer.space(src)) {
        src = src.substring(token.raw.length);
        if (token.raw.length === 1 && tokens.length > 0) {
          // if there's a single \n as a spacer, it's terminating the last line,
          // so move it there so that we don't get unecessary paragraph tags
          tokens[tokens.length - 1].raw += '\n';
        } else {
          tokens.push(token);
        }
        continue;
      }

      // code
      if (token = this.tokenizer.code(src)) {
        src = src.substring(token.raw.length);
        lastToken = tokens[tokens.length - 1];
        // An indented code block cannot interrupt a paragraph.
        if (lastToken && (lastToken.type === 'paragraph' || lastToken.type === 'text')) {
          lastToken.raw += '\n' + token.raw;
          lastToken.text += '\n' + token.text;
          this.inlineQueue[this.inlineQueue.length - 1].src = lastToken.text;
        } else {
          tokens.push(token);
        }
        continue;
      }

      // fences
      if (token = this.tokenizer.fences(src)) {
        src = src.substring(token.raw.length);
        tokens.push(token);
        continue;
      }

      // heading
      if (token = this.tokenizer.heading(src)) {
        src = src.substring(token.raw.length);
        tokens.push(token);
        continue;
      }

      // hr
      if (token = this.tokenizer.hr(src)) {
        src = src.substring(token.raw.length);
        tokens.push(token);
        continue;
      }

      // blockquote
      if (token = this.tokenizer.blockquote(src)) {
        src = src.substring(token.raw.length);
        tokens.push(token);
        continue;
      }

      // list
      if (token = this.tokenizer.list(src)) {
        src = src.substring(token.raw.length);
        tokens.push(token);
        continue;
      }

      // html
      if (token = this.tokenizer.html(src)) {
        src = src.substring(token.raw.length);
        tokens.push(token);
        continue;
      }

      // def
      if (token = this.tokenizer.def(src)) {
        src = src.substring(token.raw.length);
        lastToken = tokens[tokens.length - 1];
        if (lastToken && (lastToken.type === 'paragraph' || lastToken.type === 'text')) {
          lastToken.raw += '\n' + token.raw;
          lastToken.text += '\n' + token.raw;
          this.inlineQueue[this.inlineQueue.length - 1].src = lastToken.text;
        } else if (!this.tokens.links[token.tag]) {
          this.tokens.links[token.tag] = {
            href: token.href,
            title: token.title
          };
        }
        continue;
      }

      // table (gfm)
      if (token = this.tokenizer.table(src)) {
        src = src.substring(token.raw.length);
        tokens.push(token);
        continue;
      }

      // lheading
      if (token = this.tokenizer.lheading(src)) {
        src = src.substring(token.raw.length);
        tokens.push(token);
        continue;
      }

      // top-level paragraph
      // prevent paragraph consuming extensions by clipping 'src' to extension start
      cutSrc = src;
      if (this.options.extensions && this.options.extensions.startBlock) {
        let startIndex = Infinity;
        const tempSrc = src.slice(1);
        let tempStart;
        this.options.extensions.startBlock.forEach(function(getStartIndex) {
          tempStart = getStartIndex.call({ lexer: this }, tempSrc);
          if (typeof tempStart === 'number' && tempStart >= 0) { startIndex = Math.min(startIndex, tempStart); }
        });
        if (startIndex < Infinity && startIndex >= 0) {
          cutSrc = src.substring(0, startIndex + 1);
        }
      }
      if (this.state.top && (token = this.tokenizer.paragraph(cutSrc))) {
        lastToken = tokens[tokens.length - 1];
        if (lastParagraphClipped && lastToken.type === 'paragraph') {
          lastToken.raw += '\n' + token.raw;
          lastToken.text += '\n' + token.text;
          this.inlineQueue.pop();
          this.inlineQueue[this.inlineQueue.length - 1].src = lastToken.text;
        } else {
          tokens.push(token);
        }
        lastParagraphClipped = (cutSrc.length !== src.length);
        src = src.substring(token.raw.length);
        continue;
      }

      // text
      if (token = this.tokenizer.text(src)) {
        src = src.substring(token.raw.length);
        lastToken = tokens[tokens.length - 1];
        if (lastToken && lastToken.type === 'text') {
          lastToken.raw += '\n' + token.raw;
          lastToken.text += '\n' + token.text;
          this.inlineQueue.pop();
          this.inlineQueue[this.inlineQueue.length - 1].src = lastToken.text;
        } else {
          tokens.push(token);
        }
        continue;
      }

      if (src) {
        const errMsg = 'Infinite loop on byte: ' + src.charCodeAt(0);
        if (this.options.silent) {
          console.error(errMsg);
          break;
        } else {
          throw new Error(errMsg);
        }
      }
    }

    this.state.top = true;
    return tokens;
  }

  inline(src, tokens = []) {
    this.inlineQueue.push({ src, tokens });
    return tokens;
  }

  /**
   * Lexing/Compiling
   */
  inlineTokens(src, tokens = []) {
    let token, lastToken, cutSrc;

    // String with links masked to avoid interference with em and strong
    let maskedSrc = src;
    let match;
    let keepPrevChar, prevChar;

    // Mask out reflinks
    if (this.tokens.links) {
      const links = Object.keys(this.tokens.links);
      if (links.length > 0) {
        while ((match = this.tokenizer.rules.inline.reflinkSearch.exec(maskedSrc)) != null) {
          if (links.includes(match[0].slice(match[0].lastIndexOf('[') + 1, -1))) {
            maskedSrc = maskedSrc.slice(0, match.index) + '[' + repeatString('a', match[0].length - 2) + ']' + maskedSrc.slice(this.tokenizer.rules.inline.reflinkSearch.lastIndex);
          }
        }
      }
    }
    // Mask out other blocks
    while ((match = this.tokenizer.rules.inline.blockSkip.exec(maskedSrc)) != null) {
      maskedSrc = maskedSrc.slice(0, match.index) + '[' + repeatString('a', match[0].length - 2) + ']' + maskedSrc.slice(this.tokenizer.rules.inline.blockSkip.lastIndex);
    }

    // Mask out escaped em & strong delimiters
    while ((match = this.tokenizer.rules.inline.escapedEmSt.exec(maskedSrc)) != null) {
      maskedSrc = maskedSrc.slice(0, match.index) + '++' + maskedSrc.slice(this.tokenizer.rules.inline.escapedEmSt.lastIndex);
    }

    while (src) {
      if (!keepPrevChar) {
        prevChar = '';
      }
      keepPrevChar = false;

      // extensions
      if (this.options.extensions
        && this.options.extensions.inline
        && this.options.extensions.inline.some((extTokenizer) => {
          if (token = extTokenizer.call({ lexer: this }, src, tokens)) {
            src = src.substring(token.raw.length);
            tokens.push(token);
            return true;
          }
          return false;
        })) {
        continue;
      }

      // escape
      if (token = this.tokenizer.escape(src)) {
        src = src.substring(token.raw.length);
        tokens.push(token);
        continue;
      }

      // tag
      if (token = this.tokenizer.tag(src)) {
        src = src.substring(token.raw.length);
        lastToken = tokens[tokens.length - 1];
        if (lastToken && token.type === 'text' && lastToken.type === 'text') {
          lastToken.raw += token.raw;
          lastToken.text += token.text;
        } else {
          tokens.push(token);
        }
        continue;
      }

      // link
      if (token = this.tokenizer.link(src)) {
        src = src.substring(token.raw.length);
        tokens.push(token);
        continue;
      }

      // reflink, nolink
      if (token = this.tokenizer.reflink(src, this.tokens.links)) {
        src = src.substring(token.raw.length);
        lastToken = tokens[tokens.length - 1];
        if (lastToken && token.type === 'text' && lastToken.type === 'text') {
          lastToken.raw += token.raw;
          lastToken.text += token.text;
        } else {
          tokens.push(token);
        }
        continue;
      }

      // em & strong
      if (token = this.tokenizer.emStrong(src, maskedSrc, prevChar)) {
        src = src.substring(token.raw.length);
        tokens.push(token);
        continue;
      }

      // code
      if (token = this.tokenizer.codespan(src)) {
        src = src.substring(token.raw.length);
        tokens.push(token);
        continue;
      }

      // br
      if (token = this.tokenizer.br(src)) {
        src = src.substring(token.raw.length);
        tokens.push(token);
        continue;
      }

      // del (gfm)
      if (token = this.tokenizer.del(src)) {
        src = src.substring(token.raw.length);
        tokens.push(token);
        continue;
      }

      // autolink
      if (token = this.tokenizer.autolink(src, mangle)) {
        src = src.substring(token.raw.length);
        tokens.push(token);
        continue;
      }

      // url (gfm)
      if (!this.state.inLink && (token = this.tokenizer.url(src, mangle))) {
        src = src.substring(token.raw.length);
        tokens.push(token);
        continue;
      }

      // text
      // prevent inlineText consuming extensions by clipping 'src' to extension start
      cutSrc = src;
      if (this.options.extensions && this.options.extensions.startInline) {
        let startIndex = Infinity;
        const tempSrc = src.slice(1);
        let tempStart;
        this.options.extensions.startInline.forEach(function(getStartIndex) {
          tempStart = getStartIndex.call({ lexer: this }, tempSrc);
          if (typeof tempStart === 'number' && tempStart >= 0) { startIndex = Math.min(startIndex, tempStart); }
        });
        if (startIndex < Infinity && startIndex >= 0) {
          cutSrc = src.substring(0, startIndex + 1);
        }
      }
      if (token = this.tokenizer.inlineText(cutSrc, smartypants)) {
        src = src.substring(token.raw.length);
        if (token.raw.slice(-1) !== '_') { // Track prevChar before string of ____ started
          prevChar = token.raw.slice(-1);
        }
        keepPrevChar = true;
        lastToken = tokens[tokens.length - 1];
        if (lastToken && lastToken.type === 'text') {
          lastToken.raw += token.raw;
          lastToken.text += token.text;
        } else {
          tokens.push(token);
        }
        continue;
      }

      if (src) {
        const errMsg = 'Infinite loop on byte: ' + src.charCodeAt(0);
        if (this.options.silent) {
          console.error(errMsg);
          break;
        } else {
          throw new Error(errMsg);
        }
      }
    }

    return tokens;
  }
}

/**
 * Renderer
 */
class Renderer {
  constructor(options) {
    this.options = options || defaults;
  }

  code(code, infostring, escaped) {
    const lang = (infostring || '').match(/\S*/)[0];
    if (this.options.highlight) {
      const out = this.options.highlight(code, lang);
      if (out != null && out !== code) {
        escaped = true;
        code = out;
      }
    }

    code = code.replace(/\n$/, '') + '\n';

    if (!lang) {
      return '<pre><code>'
        + (escaped ? code : escape(code, true))
        + '</code></pre>\n';
    }

    return '<pre><code class="'
      + this.options.langPrefix
      + escape(lang, true)
      + '">'
      + (escaped ? code : escape(code, true))
      + '</code></pre>\n';
  }

  /**
   * @param {string} quote
   */
  blockquote(quote) {
    return `<blockquote>\n${quote}</blockquote>\n`;
  }

  html(html) {
    return html;
  }

  /**
   * @param {string} text
   * @param {string} level
   * @param {string} raw
   * @param {any} slugger
   */
  heading(text, level, raw, slugger) {
    if (this.options.headerIds) {
      const id = this.options.headerPrefix + slugger.slug(raw);
      return `<h${level} id="${id}">${text}</h${level}>\n`;
    }

    // ignore IDs
    return `<h${level}>${text}</h${level}>\n`;
  }

  hr() {
    return this.options.xhtml ? '<hr/>\n' : '<hr>\n';
  }

  list(body, ordered, start) {
    const type = ordered ? 'ol' : 'ul',
      startatt = (ordered && start !== 1) ? (' start="' + start + '"') : '';
    return '<' + type + startatt + '>\n' + body + '</' + type + '>\n';
  }

  /**
   * @param {string} text
   */
  listitem(text) {
    return `<li>${text}</li>\n`;
  }

  checkbox(checked) {
    return '<input '
      + (checked ? 'checked="" ' : '')
      + 'disabled="" type="checkbox"'
      + (this.options.xhtml ? ' /' : '')
      + '> ';
  }

  /**
   * @param {string} text
   */
  paragraph(text) {
    return `<p>${text}</p>\n`;
  }

  /**
   * @param {string} header
   * @param {string} body
   */
  table(header, body) {
    if (body) body = `<tbody>${body}</tbody>`;

    return '<table>\n'
      + '<thead>\n'
      + header
      + '</thead>\n'
      + body
      + '</table>\n';
  }

  /**
   * @param {string} content
   */
  tablerow(content) {
    return `<tr>\n${content}</tr>\n`;
  }

  tablecell(content, flags) {
    const type = flags.header ? 'th' : 'td';
    const tag = flags.align
      ? `<${type} align="${flags.align}">`
      : `<${type}>`;
    return tag + content + `</${type}>\n`;
  }

  /**
   * span level renderer
   * @param {string} text
   */
  strong(text) {
    return `<strong>${text}</strong>`;
  }

  /**
   * @param {string} text
   */
  em(text) {
    return `<em>${text}</em>`;
  }

  /**
   * @param {string} text
   */
  codespan(text) {
    return `<code>${text}</code>`;
  }

  br() {
    return this.options.xhtml ? '<br/>' : '<br>';
  }

  /**
   * @param {string} text
   */
  del(text) {
    return `<del>${text}</del>`;
  }

  /**
   * @param {string} href
   * @param {string} title
   * @param {string} text
   */
  link(href, title, text) {
    href = cleanUrl(this.options.sanitize, this.options.baseUrl, href);
    if (href === null) {
      return text;
    }
    let out = '<a href="' + escape(href) + '"';
    if (title) {
      out += ' title="' + title + '"';
    }
    out += '>' + text + '</a>';
    return out;
  }

  /**
   * @param {string} href
   * @param {string} title
   * @param {string} text
   */
  image(href, title, text) {
    href = cleanUrl(this.options.sanitize, this.options.baseUrl, href);
    if (href === null) {
      return text;
    }

    let out = `<img src="${href}" alt="${text}"`;
    if (title) {
      out += ` title="${title}"`;
    }
    out += this.options.xhtml ? '/>' : '>';
    return out;
  }

  text(text) {
    return text;
  }
}

/**
 * TextRenderer
 * returns only the textual part of the token
 */
class TextRenderer {
  // no need for block level renderers
  strong(text) {
    return text;
  }

  em(text) {
    return text;
  }

  codespan(text) {
    return text;
  }

  del(text) {
    return text;
  }

  html(text) {
    return text;
  }

  text(text) {
    return text;
  }

  link(href, title, text) {
    return '' + text;
  }

  image(href, title, text) {
    return '' + text;
  }

  br() {
    return '';
  }
}

/**
 * Slugger generates header id
 */
class Slugger {
  constructor() {
    this.seen = {};
  }

  /**
   * @param {string} value
   */
  serialize(value) {
    return value
      .toLowerCase()
      .trim()
      // remove html tags
      .replace(/<[!\/a-z].*?>/ig, '')
      // remove unwanted chars
      .replace(/[\u2000-\u206F\u2E00-\u2E7F\\'!"#$%&()*+,./:;<=>?@[\]^`{|}~]/g, '')
      .replace(/\s/g, '-');
  }

  /**
   * Finds the next safe (unique) slug to use
   * @param {string} originalSlug
   * @param {boolean} isDryRun
   */
  getNextSafeSlug(originalSlug, isDryRun) {
    let slug = originalSlug;
    let occurenceAccumulator = 0;
    if (this.seen.hasOwnProperty(slug)) {
      occurenceAccumulator = this.seen[originalSlug];
      do {
        occurenceAccumulator++;
        slug = originalSlug + '-' + occurenceAccumulator;
      } while (this.seen.hasOwnProperty(slug));
    }
    if (!isDryRun) {
      this.seen[originalSlug] = occurenceAccumulator;
      this.seen[slug] = 0;
    }
    return slug;
  }

  /**
   * Convert string to unique id
   * @param {object} [options]
   * @param {boolean} [options.dryrun] Generates the next unique slug without
   * updating the internal accumulator.
   */
  slug(value, options = {}) {
    const slug = this.serialize(value);
    return this.getNextSafeSlug(slug, options.dryrun);
  }
}

/**
 * Parsing & Compiling
 */
class Parser {
  constructor(options) {
    this.options = options || defaults;
    this.options.renderer = this.options.renderer || new Renderer();
    this.renderer = this.options.renderer;
    this.renderer.options = this.options;
    this.textRenderer = new TextRenderer();
    this.slugger = new Slugger();
  }

  /**
   * Static Parse Method
   */
  static parse(tokens, options) {
    const parser = new Parser(options);
    return parser.parse(tokens);
  }

  /**
   * Static Parse Inline Method
   */
  static parseInline(tokens, options) {
    const parser = new Parser(options);
    return parser.parseInline(tokens);
  }

  /**
   * Parse Loop
   */
  parse(tokens, top = true) {
    let out = '',
      i,
      j,
      k,
      l2,
      l3,
      row,
      cell,
      header,
      body,
      token,
      ordered,
      start,
      loose,
      itemBody,
      item,
      checked,
      task,
      checkbox,
      ret;

    const l = tokens.length;
    for (i = 0; i < l; i++) {
      token = tokens[i];

      // Run any renderer extensions
      if (this.options.extensions && this.options.extensions.renderers && this.options.extensions.renderers[token.type]) {
        ret = this.options.extensions.renderers[token.type].call({ parser: this }, token);
        if (ret !== false || !['space', 'hr', 'heading', 'code', 'table', 'blockquote', 'list', 'html', 'paragraph', 'text'].includes(token.type)) {
          out += ret || '';
          continue;
        }
      }

      switch (token.type) {
        case 'space': {
          continue;
        }
        case 'hr': {
          out += this.renderer.hr();
          continue;
        }
        case 'heading': {
          out += this.renderer.heading(
            this.parseInline(token.tokens),
            token.depth,
            unescape(this.parseInline(token.tokens, this.textRenderer)),
            this.slugger);
          continue;
        }
        case 'code': {
          out += this.renderer.code(token.text,
            token.lang,
            token.escaped);
          continue;
        }
        case 'table': {
          header = '';

          // header
          cell = '';
          l2 = token.header.length;
          for (j = 0; j < l2; j++) {
            cell += this.renderer.tablecell(
              this.parseInline(token.header[j].tokens),
              { header: true, align: token.align[j] }
            );
          }
          header += this.renderer.tablerow(cell);

          body = '';
          l2 = token.rows.length;
          for (j = 0; j < l2; j++) {
            row = token.rows[j];

            cell = '';
            l3 = row.length;
            for (k = 0; k < l3; k++) {
              cell += this.renderer.tablecell(
                this.parseInline(row[k].tokens),
                { header: false, align: token.align[k] }
              );
            }

            body += this.renderer.tablerow(cell);
          }
          out += this.renderer.table(header, body);
          continue;
        }
        case 'blockquote': {
          body = this.parse(token.tokens);
          out += this.renderer.blockquote(body);
          continue;
        }
        case 'list': {
          ordered = token.ordered;
          start = token.start;
          loose = token.loose;
          l2 = token.items.length;

          body = '';
          for (j = 0; j < l2; j++) {
            item = token.items[j];
            checked = item.checked;
            task = item.task;

            itemBody = '';
            if (item.task) {
              checkbox = this.renderer.checkbox(checked);
              if (loose) {
                if (item.tokens.length > 0 && item.tokens[0].type === 'paragraph') {
                  item.tokens[0].text = checkbox + ' ' + item.tokens[0].text;
                  if (item.tokens[0].tokens && item.tokens[0].tokens.length > 0 && item.tokens[0].tokens[0].type === 'text') {
                    item.tokens[0].tokens[0].text = checkbox + ' ' + item.tokens[0].tokens[0].text;
                  }
                } else {
                  item.tokens.unshift({
                    type: 'text',
                    text: checkbox
                  });
                }
              } else {
                itemBody += checkbox;
              }
            }

            itemBody += this.parse(item.tokens, loose);
            body += this.renderer.listitem(itemBody, task, checked);
          }

          out += this.renderer.list(body, ordered, start);
          continue;
        }
        case 'html': {
          // TODO parse inline content if parameter markdown=1
          out += this.renderer.html(token.text);
          continue;
        }
        case 'paragraph': {
          out += this.renderer.paragraph(this.parseInline(token.tokens));
          continue;
        }
        case 'text': {
          body = token.tokens ? this.parseInline(token.tokens) : token.text;
          while (i + 1 < l && tokens[i + 1].type === 'text') {
            token = tokens[++i];
            body += '\n' + (token.tokens ? this.parseInline(token.tokens) : token.text);
          }
          out += top ? this.renderer.paragraph(body) : body;
          continue;
        }

        default: {
          const errMsg = 'Token with "' + token.type + '" type was not found.';
          if (this.options.silent) {
            console.error(errMsg);
            return;
          } else {
            throw new Error(errMsg);
          }
        }
      }
    }

    return out;
  }

  /**
   * Parse Inline Tokens
   */
  parseInline(tokens, renderer) {
    renderer = renderer || this.renderer;
    let out = '',
      i,
      token,
      ret;

    const l = tokens.length;
    for (i = 0; i < l; i++) {
      token = tokens[i];

      // Run any renderer extensions
      if (this.options.extensions && this.options.extensions.renderers && this.options.extensions.renderers[token.type]) {
        ret = this.options.extensions.renderers[token.type].call({ parser: this }, token);
        if (ret !== false || !['escape', 'html', 'link', 'image', 'strong', 'em', 'codespan', 'br', 'del', 'text'].includes(token.type)) {
          out += ret || '';
          continue;
        }
      }

      switch (token.type) {
        case 'escape': {
          out += renderer.text(token.text);
          break;
        }
        case 'html': {
          out += renderer.html(token.text);
          break;
        }
        case 'link': {
          out += renderer.link(token.href, token.title, this.parseInline(token.tokens, renderer));
          break;
        }
        case 'image': {
          out += renderer.image(token.href, token.title, token.text);
          break;
        }
        case 'strong': {
          out += renderer.strong(this.parseInline(token.tokens, renderer));
          break;
        }
        case 'em': {
          out += renderer.em(this.parseInline(token.tokens, renderer));
          break;
        }
        case 'codespan': {
          out += renderer.codespan(token.text);
          break;
        }
        case 'br': {
          out += renderer.br();
          break;
        }
        case 'del': {
          out += renderer.del(this.parseInline(token.tokens, renderer));
          break;
        }
        case 'text': {
          out += renderer.text(token.text);
          break;
        }
        default: {
          const errMsg = 'Token with "' + token.type + '" type was not found.';
          if (this.options.silent) {
            console.error(errMsg);
            return;
          } else {
            throw new Error(errMsg);
          }
        }
      }
    }
    return out;
  }
}

/**
 * Marked
 */
function marked(src, opt, callback) {
  // throw error in case of non string input
  if (typeof src === 'undefined' || src === null) {
    throw new Error('marked(): input parameter is undefined or null');
  }
  if (typeof src !== 'string') {
    throw new Error('marked(): input parameter is of type '
      + Object.prototype.toString.call(src) + ', string expected');
  }

  if (typeof opt === 'function') {
    callback = opt;
    opt = null;
  }

  opt = merge({}, marked.defaults, opt || {});
  checkSanitizeDeprecation(opt);

  if (callback) {
    const highlight = opt.highlight;
    let tokens;

    try {
      tokens = Lexer.lex(src, opt);
    } catch (e) {
      return callback(e);
    }

    const done = function(err) {
      let out;

      if (!err) {
        try {
          if (opt.walkTokens) {
            marked.walkTokens(tokens, opt.walkTokens);
          }
          out = Parser.parse(tokens, opt);
        } catch (e) {
          err = e;
        }
      }

      opt.highlight = highlight;

      return err
        ? callback(err)
        : callback(null, out);
    };

    if (!highlight || highlight.length < 3) {
      return done();
    }

    delete opt.highlight;

    if (!tokens.length) return done();

    let pending = 0;
    marked.walkTokens(tokens, function(token) {
      if (token.type === 'code') {
        pending++;
        setTimeout(() => {
          highlight(token.text, token.lang, function(err, code) {
            if (err) {
              return done(err);
            }
            if (code != null && code !== token.text) {
              token.text = code;
              token.escaped = true;
            }

            pending--;
            if (pending === 0) {
              done();
            }
          });
        }, 0);
      }
    });

    if (pending === 0) {
      done();
    }

    return;
  }

  try {
    const tokens = Lexer.lex(src, opt);
    if (opt.walkTokens) {
      marked.walkTokens(tokens, opt.walkTokens);
    }
    return Parser.parse(tokens, opt);
  } catch (e) {
    e.message += '\nPlease report this to https://github.com/markedjs/marked.';
    if (opt.silent) {
      return '<p>An error occurred:</p><pre>'
        + escape(e.message + '', true)
        + '</pre>';
    }
    throw e;
  }
}

/**
 * Options
 */

marked.options =
marked.setOptions = function(opt) {
  merge(marked.defaults, opt);
  changeDefaults(marked.defaults);
  return marked;
};

marked.getDefaults = getDefaults;

marked.defaults = defaults;

/**
 * Use Extension
 */

marked.use = function(...args) {
  const opts = merge({}, ...args);
  const extensions = marked.defaults.extensions || { renderers: {}, childTokens: {} };
  let hasExtensions;

  args.forEach((pack) => {
    // ==-- Parse "addon" extensions --== //
    if (pack.extensions) {
      hasExtensions = true;
      pack.extensions.forEach((ext) => {
        if (!ext.name) {
          throw new Error('extension name required');
        }
        if (ext.renderer) { // Renderer extensions
          const prevRenderer = extensions.renderers ? extensions.renderers[ext.name] : null;
          if (prevRenderer) {
            // Replace extension with func to run new extension but fall back if false
            extensions.renderers[ext.name] = function(...args) {
              let ret = ext.renderer.apply(this, args);
              if (ret === false) {
                ret = prevRenderer.apply(this, args);
              }
              return ret;
            };
          } else {
            extensions.renderers[ext.name] = ext.renderer;
          }
        }
        if (ext.tokenizer) { // Tokenizer Extensions
          if (!ext.level || (ext.level !== 'block' && ext.level !== 'inline')) {
            throw new Error("extension level must be 'block' or 'inline'");
          }
          if (extensions[ext.level]) {
            extensions[ext.level].unshift(ext.tokenizer);
          } else {
            extensions[ext.level] = [ext.tokenizer];
          }
          if (ext.start) { // Function to check for start of token
            if (ext.level === 'block') {
              if (extensions.startBlock) {
                extensions.startBlock.push(ext.start);
              } else {
                extensions.startBlock = [ext.start];
              }
            } else if (ext.level === 'inline') {
              if (extensions.startInline) {
                extensions.startInline.push(ext.start);
              } else {
                extensions.startInline = [ext.start];
              }
            }
          }
        }
        if (ext.childTokens) { // Child tokens to be visited by walkTokens
          extensions.childTokens[ext.name] = ext.childTokens;
        }
      });
    }

    // ==-- Parse "overwrite" extensions --== //
    if (pack.renderer) {
      const renderer = marked.defaults.renderer || new Renderer();
      for (const prop in pack.renderer) {
        const prevRenderer = renderer[prop];
        // Replace renderer with func to run extension, but fall back if false
        renderer[prop] = (...args) => {
          let ret = pack.renderer[prop].apply(renderer, args);
          if (ret === false) {
            ret = prevRenderer.apply(renderer, args);
          }
          return ret;
        };
      }
      opts.renderer = renderer;
    }
    if (pack.tokenizer) {
      const tokenizer = marked.defaults.tokenizer || new Tokenizer();
      for (const prop in pack.tokenizer) {
        const prevTokenizer = tokenizer[prop];
        // Replace tokenizer with func to run extension, but fall back if false
        tokenizer[prop] = (...args) => {
          let ret = pack.tokenizer[prop].apply(tokenizer, args);
          if (ret === false) {
            ret = prevTokenizer.apply(tokenizer, args);
          }
          return ret;
        };
      }
      opts.tokenizer = tokenizer;
    }

    // ==-- Parse WalkTokens extensions --== //
    if (pack.walkTokens) {
      const walkTokens = marked.defaults.walkTokens;
      opts.walkTokens = function(token) {
        pack.walkTokens.call(this, token);
        if (walkTokens) {
          walkTokens.call(this, token);
        }
      };
    }

    if (hasExtensions) {
      opts.extensions = extensions;
    }

    marked.setOptions(opts);
  });
};

/**
 * Run callback for every token
 */

marked.walkTokens = function(tokens, callback) {
  for (const token of tokens) {
    callback.call(marked, token);
    switch (token.type) {
      case 'table': {
        for (const cell of token.header) {
          marked.walkTokens(cell.tokens, callback);
        }
        for (const row of token.rows) {
          for (const cell of row) {
            marked.walkTokens(cell.tokens, callback);
          }
        }
        break;
      }
      case 'list': {
        marked.walkTokens(token.items, callback);
        break;
      }
      default: {
        if (marked.defaults.extensions && marked.defaults.extensions.childTokens && marked.defaults.extensions.childTokens[token.type]) { // Walk any extensions
          marked.defaults.extensions.childTokens[token.type].forEach(function(childTokens) {
            marked.walkTokens(token[childTokens], callback);
          });
        } else if (token.tokens) {
          marked.walkTokens(token.tokens, callback);
        }
      }
    }
  }
};

/**
 * Parse Inline
 * @param {string} src
 */
marked.parseInline = function(src, opt) {
  // throw error in case of non string input
  if (typeof src === 'undefined' || src === null) {
    throw new Error('marked.parseInline(): input parameter is undefined or null');
  }
  if (typeof src !== 'string') {
    throw new Error('marked.parseInline(): input parameter is of type '
      + Object.prototype.toString.call(src) + ', string expected');
  }

  opt = merge({}, marked.defaults, opt || {});
  checkSanitizeDeprecation(opt);

  try {
    const tokens = Lexer.lexInline(src, opt);
    if (opt.walkTokens) {
      marked.walkTokens(tokens, opt.walkTokens);
    }
    return Parser.parseInline(tokens, opt);
  } catch (e) {
    e.message += '\nPlease report this to https://github.com/markedjs/marked.';
    if (opt.silent) {
      return '<p>An error occurred:</p><pre>'
        + escape(e.message + '', true)
        + '</pre>';
    }
    throw e;
  }
};

/**
 * Expose
 */
marked.Parser = Parser;
marked.parser = Parser.parse;
marked.Renderer = Renderer;
marked.TextRenderer = TextRenderer;
marked.Lexer = Lexer;
marked.lexer = Lexer.lex;
marked.Tokenizer = Tokenizer;
marked.Slugger = Slugger;
marked.parse = marked;

const options = marked.options;
const setOptions = marked.setOptions;
const use = marked.use;
const walkTokens = marked.walkTokens;
const parseInline = marked.parseInline;
const parse = marked;
const parser = Parser.parse;
const lexer = Lexer.lex;

export { Lexer, Parser, Renderer, Slugger, TextRenderer, Tokenizer, defaults, getDefaults, lexer, marked, options, parse, parseInline, parser, setOptions, use, walkTokens };