chore(monorepo/server): integrate turndown-plugin-gfm

packages/turndown-plugin-gfm/src/gfm.js

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+import highlightedCodeBlock from './highlighted-code-block.js'
+import strikethrough from './strikethrough.js'
+import tables from './tables.js'
+import taskListItems from './task-list-items.js'
+
+function gfm (turndownService) {
+  turndownService.use([
+    highlightedCodeBlock,
+    strikethrough,
+    tables,
+    taskListItems
+  ])
+}
+
+export { gfm, highlightedCodeBlock, strikethrough, tables, taskListItems }

packages/turndown-plugin-gfm/src/highlighted-code-block.js

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+var highlightRegExp = /highlight-(?:text|source)-([a-z0-9]+)/
+
+export default 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'
+      )
+    }
+  })
+}

packages/turndown-plugin-gfm/src/strikethrough.js

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

packages/turndown-plugin-gfm/src/tables.js

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+var indexOf = Array.prototype.indexOf
+var every = Array.prototype.every
+var rules = {}
+var alignMap = { left: ':---', right: '---:', center: ':---:' };
+
+let isCodeBlock_ = null;
+let options_ = null;
+
+// We need to cache the result of tableShouldBeSkipped() as it is expensive.
+// Caching it means we went from about 9000 ms for rendering down to 90 ms.
+// Fixes https://github.com/laurent22/joplin/issues/6736
+const tableShouldBeSkippedCache_ = new WeakMap();
+
+function getAlignment(node) {
+  return node ? (node.getAttribute('align') || node.style.textAlign || '').toLowerCase() : '';
+}
+
+function getBorder(alignment) {
+  return alignment ? alignMap[alignment] : '---';
+}
+
+function getColumnAlignment(table, columnIndex) {
+  var votes = {
+    left: 0,
+    right: 0,
+    center: 0,
+    '': 0,
+  };
+
+  var align = '';
+
+  for (var i = 0; i < table.rows.length; ++i) {
+    var row = table.rows[i];
+    if (columnIndex < row.childNodes.length) {
+      var cellAlignment = getAlignment(row.childNodes[columnIndex]);
+      ++votes[cellAlignment];
+
+      if (votes[cellAlignment] > votes[align]) {
+        align = cellAlignment;
+      }
+    }
+  }
+
+  return align;
+}
+
+rules.tableCell = {
+  filter: ['th', 'td'],
+  replacement: function (content, node) {
+    if (tableShouldBeSkipped(nodeParentTable(node))) return content;
+    return cell(content, node)
+  }
+}
+
+rules.tableRow = {
+  filter: 'tr',
+  replacement: function (content, node) {
+    const parentTable = nodeParentTable(node);
+    if (tableShouldBeSkipped(parentTable)) return content;
+
+    var borderCells = ''
+
+    if (isHeadingRow(node)) {
+      const colCount = tableColCount(parentTable);
+      for (var i = 0; i < colCount; i++) {
+        const childNode = i < node.childNodes.length ? node.childNodes[i] : null;
+        var border = getBorder(getColumnAlignment(parentTable, i));
+        borderCells += cell(border, childNode, i);
+      }
+    }
+    return '\n' + content + (borderCells ? '\n' + borderCells : '')
+  }
+}
+
+rules.table = {
+  filter: function (node, options) {
+    return node.nodeName === 'TABLE';
+  },
+
+  replacement: function (content, node) {
+    // Only convert tables that can result in valid Markdown
+    // Other tables are kept as HTML using `keep` (see below).
+    if (tableShouldBeHtml(node, options_)) {
+      return node.outerHTML;
+    } else {
+      if (tableShouldBeSkipped(node)) return content;
+
+      // Ensure there are no blank lines
+      content = content.replace(/\n+/g, '\n')
+
+      // If table has no heading, add an empty one so as to get a valid Markdown table
+      var secondLine = content.trim().split('\n');
+      if (secondLine.length >= 2) secondLine = secondLine[1]
+      var secondLineIsDivider = /\| :?---/.test(secondLine);
+
+      var columnCount = tableColCount(node);
+      var emptyHeader = ''
+      if (columnCount && !secondLineIsDivider) {
+        emptyHeader = '|' + '     |'.repeat(columnCount) + '\n' + '|'
+        for (var columnIndex = 0; columnIndex < columnCount; ++columnIndex) {
+          emptyHeader += ' ' + getBorder(getColumnAlignment(node, columnIndex)) + ' |';
+        }
+      }
+
+      const captionContent = node.caption ? node.caption.textContent || '' : '';
+      const caption = captionContent ? `${captionContent}\n\n` : '';
+      const tableContent = `${emptyHeader}${content}`.trimStart();
+      return `\n\n${caption}${tableContent}\n\n`;
+    }
+  }
+}
+
+rules.tableCaption = {
+  filter: ['caption'],
+  replacement: () => '',
+};
+
+rules.tableColgroup = {
+  filter: ['colgroup', 'col'],
+  replacement: () => '',
+};
+
+rules.tableSection = {
+  filter: ['thead', 'tbody', 'tfoot'],
+  replacement: function (content) {
+    return content
+  }
+}
+
+// A tr is a heading row if:
+// - the parent is a THEAD
+// - or if its the first child of the TABLE or the first TBODY (possibly
+//   following a blank THEAD)
+// - and every cell is a TH
+function isHeadingRow (tr) {
+  var parentNode = tr.parentNode
+  return (
+    parentNode.nodeName === 'THEAD' ||
+    (
+      parentNode.firstChild === tr &&
+      (parentNode.nodeName === 'TABLE' || isFirstTbody(parentNode)) &&
+      every.call(tr.childNodes, function (n) { return n.nodeName === 'TH' })
+    )
+  )
+}
+
+function isFirstTbody (element) {
+  var previousSibling = element.previousSibling
+  return (
+    element.nodeName === 'TBODY' && (
+      !previousSibling ||
+      (
+        previousSibling.nodeName === 'THEAD' &&
+        /^\s*$/i.test(previousSibling.textContent)
+      )
+    )
+  )
+}
+
+function cell (content, node = null, index = null) {
+  if (index === null) index = indexOf.call(node.parentNode.childNodes, node)
+  var prefix = ' '
+  if (index === 0) prefix = '| '
+  let filteredContent = content.trim().replace(/\n\r/g, '<br>').replace(/\n/g, "<br>");
+  filteredContent = filteredContent.replace(/\|+/g, '\\|')
+  while (filteredContent.length < 3) filteredContent += ' ';
+  if (node) filteredContent = handleColSpan(filteredContent, node, ' ');
+  return prefix + filteredContent + ' |'
+}
+
+function nodeContainsTable(node) {
+  if (!node.childNodes) return false;
+
+  for (let i = 0; i < node.childNodes.length; i++) {
+    const child = node.childNodes[i];
+    if (child.nodeName === 'TABLE') return true;
+    if (nodeContainsTable(child)) return true;
+  }
+  return false;
+}
+
+const nodeContains = (node, types) => {
+  if (!node.childNodes) return false;
+
+  for (let i = 0; i < node.childNodes.length; i++) {
+    const child = node.childNodes[i];
+    if (types === 'code' && isCodeBlock_ && isCodeBlock_(child)) return true;
+    if (types.includes(child.nodeName)) return true;
+    if (nodeContains(child, types)) return true;
+  }
+
+  return false;
+}
+
+const tableShouldBeHtml = (tableNode, options) => {
+  const possibleTags = [
+    'UL',
+    'OL',
+    'H1',
+    'H2',
+    'H3',
+    'H4',
+    'H5',
+    'H6',
+    'HR',
+    'BLOCKQUOTE',
+    'PRE'
+  ];
+
+  // In general we should leave as HTML tables that include other tables. The
+  // exception is with the Web Clipper when we import a web page with a layout
+  // that's made of HTML tables. In that case we have this logic of removing the
+  // outer table and keeping only the inner ones. For the Rich Text editor
+  // however we always want to keep nested tables.
+  if (options.preserveNestedTables) possibleTags.push('TABLE');
+
+  return nodeContains(tableNode, 'code') ||
+    nodeContains(tableNode, possibleTags);
+}
+
+// Various conditions under which a table should be skipped - i.e. each cell
+// will be rendered one after the other as if they were paragraphs.
+function tableShouldBeSkipped(tableNode) {
+  const cached = tableShouldBeSkippedCache_.get(tableNode);
+  if (cached !== undefined) return cached;
+
+  const result = tableShouldBeSkipped_(tableNode);
+
+  tableShouldBeSkippedCache_.set(tableNode, result);
+  return result;
+}
+
+function tableShouldBeSkipped_(tableNode) {
+  if (!tableNode) return true;
+  if (!tableNode.rows) return true;
+  if (tableNode.rows.length === 1 && tableNode.rows[0].childNodes.length <= 1) return true; // Table with only one cell
+  if (nodeContainsTable(tableNode)) return true;
+  return false;
+}
+
+function nodeParentDiv(node) {
+  let parent = node.parentNode;
+  while (parent.nodeName !== 'DIV') {
+    parent = parent.parentNode;
+    if (!parent) return null;
+  }
+  return parent;
+}
+
+function nodeParentTable(node) {
+  let parent = node.parentNode;
+  while (parent.nodeName !== 'TABLE') {
+    parent = parent.parentNode;
+    if (!parent) return null;
+  }
+  return parent;
+}
+
+function handleColSpan(content, node, emptyChar) {
+  const colspan = node.getAttribute('colspan') || 1;
+  for (let i = 1; i < colspan; i++) {
+    content += ' | ' + emptyChar.repeat(3);
+  }
+  return content
+}
+
+function tableColCount(node) {
+  let maxColCount = 0;
+  for (let i = 0; i < node.rows.length; i++) {
+    const row = node.rows[i]
+    const colCount = row.childNodes.length
+    if (colCount > maxColCount) maxColCount = colCount
+  }
+  return maxColCount
+}
+
+export default function tables (turndownService) {
+  isCodeBlock_ = turndownService.isCodeBlock;
+  options_ = turndownService.options;
+
+  turndownService.keep(function (node) {
+    if (node.nodeName === 'TABLE' && tableShouldBeHtml(node, turndownService.options)) return true;
+    return false;
+  });
+  for (var key in rules) turndownService.addRule(key, rules[key])
+}

packages/turndown-plugin-gfm/src/task-list-items.js

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+export default 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]' : '[ ]') + ' '
+    }
+  })
+}