@guyplusplus/turndown-plugin-gfm/lib/turndown-plugin-gfm.cjs.js

Turndown plugin to add GitHub Flavored Markdown extensions.

'use strict';

Object.defineProperty(exports, '__esModule', { value: true });

var highlightRegExp = /highlight-(?:text|source)-([a-z0-9]+)/;

function highlightedCodeBlock (turndownService) {
  turndownService.addRule('highlightedCodeBlock', {
    filter: function (node) {
      var firstChild = node.firstChild;
      return (
        node.nodeName === 'DIV' &&
        highlightRegExp.test(node.className) &&
        firstChild &&
        firstChild.nodeName === 'PRE'
      )
    },
    replacement: function (content, node, options) {
      var className = node.className || '';
      var language = (className.match(highlightRegExp) || [null, ''])[1];

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

function strikethrough (turndownService) {
  turndownService.addRule('strikethrough', {
    filter: ['del', 's', 'strike'],
    replacement: function (content) {
      return '~' + content + '~'
    }
  });
}

var indexOf = Array.prototype.indexOf;
var rules = {};

rules.tableCell = {
  filter: ['th', 'td'],
  replacement: function (content, node) {
    return cell(content, node) + spannedCells(node, '')
  }
};

rules.tableRow = {
  filter: 'tr',
  replacement: function (content, node) {
    var borderCells = '';
    var alignMap = { left: ':--', right: '--:', center: ':-:' };

    if (isHeadingRow(node)) {
      for (var i = 0; i < node.childNodes.length; i++) {
        var border = '---';
        var align = (
          node.childNodes[i].getAttribute('align') || ''
        ).toLowerCase();

        if (align) border = alignMap[align] || border;

        borderCells += cell(border, node.childNodes[i]) + spannedCells(node.childNodes[i], border);
      }
    }
    return '\n' + content + (borderCells ? '\n' + borderCells : '')
  }
};

rules.table = {
  // Only convert tables that are not nested in another table, they are kept using `keep` (see below).
  // TODO: nested tables should be converted to plain text in a strict (non HTML) gfm
  filter: function (node) {
    return node.nodeName === 'TABLE' && !isNestedTable(node)
  },

  replacement: function (content) {
    // Ensure there are no blank lines
    content = content.replace('\n\n', '\n');
    return '\n\n' + content + '\n\n'
  }
};

rules.tableSection = {
  filter: ['thead', 'tbody', 'tfoot'],
  replacement: function (content) {
    return content
  }
};

rules.captionSection = {
  // only return content if caption if the first node immediately after TABLE
  filter: 'caption',
  replacement: function (content, node) {
    if (node.parentNode.nodeName === 'TABLE' && node.parentNode.childNodes[0] === node) return content
    return ''
  }
};

function isHeadingRow (tr) {
  var parentNode = tr.parentNode;
  var tableNode = parentNode;
  if (parentNode.nodeName === 'THEAD' ||
     parentNode.nodeName === 'TFOOT' ||
     parentNode.nodeName === 'TBODY') {
    tableNode = parentNode.parentNode;
  }
  return (tableNode.nodeName === 'TABLE' && tableNode.rows[0] === tr)
}

function cell (content, node) {
  var index = indexOf.call(node.parentNode.childNodes, node);
  var prefix = ' ';
  if (index === 0) prefix = '| ';
  // Ensure single line per cell (both windows and unix EoL)
  // TODO: allow gfm non-strict mode to replace new lines by `<br/>`
  content = content.replace(/\r\n/g, '\n').replace(/\n/g, ' ');
  // | must be escaped as \|
  content = content.replace(/\|/g, '\\|');
  return prefix + content + ' |'
}

function spannedCells (node, spannedCellContent) {
  var colspan = node.getAttribute('colspan') || 1;
  if (colspan <= 1) return ''
  return (' ' + spannedCellContent + ' |').repeat(colspan - 1)
}

function isNestedTable (tableNode) {
  var currentNode = tableNode.parentNode;
  while (currentNode) {
    if (currentNode.nodeName === 'TABLE') return true
    currentNode = currentNode.parentNode;
  }
  return false
}

function tables (turndownService) {
  turndownService.keep(function (node) {
    return node.nodeName === 'TABLE' && isNestedTable(node)
  });
  for (var key in rules) turndownService.addRule(key, rules[key]);
}

function taskListItems (turndownService) {
  turndownService.addRule('taskListItems', {
    filter: function (node) {
      return node.type === 'checkbox' && node.parentNode.nodeName === 'LI'
    },
    replacement: function (content, node) {
      return (node.checked ? '[x]' : '[ ]') + ' '
    }
  });
}

function gfm (turndownService) {
  turndownService.use([
    highlightedCodeBlock,
    strikethrough,
    tables,
    taskListItems
  ]);
}

exports.gfm = gfm;
exports.highlightedCodeBlock = highlightedCodeBlock;
exports.strikethrough = strikethrough;
exports.tables = tables;
exports.taskListItems = taskListItems;