feat(editor): add CSV-to-markdown-table toolbar converter

Amit Haridas

src/utils/csv-to-markdown-table.js

@@ -0,0 +1,73 @@
+/**
+ * CSV-to-markdown-table converter
+ * Pure client-side conversion for the editor toolbar action — no Pandoc round-trip.
+ * Parses basic CSV: comma-separated fields, optional double-quote wrapping that may
+ * contain commas (with "" as an escaped quote), ragged rows padded with empty cells.
+ */
+
+/**
+ * Parse a single CSV line into field values.
+ * @param {string} line - One CSV line (no line breaks).
+ * @returns {string[]} Field values for the line.
+ */
+function parseCsvLine(line) {
+  const cells = [];
+  let current = '';
+  let inQuotes = false;
+  for (let i = 0; i < line.length; i++) {
+    const char = line[i];
+    if (inQuotes) {
+      if (char === '"') {
+        if (line[i + 1] === '"') {
+          current += '"';
+          i++;
+        } else {
+          inQuotes = false;
+        }
+      } else {
+        current += char;
+      }
+    } else if (char === '"') {
+      inQuotes = true;
+    } else if (char === ',') {
+      cells.push(current);
+      current = '';
+    } else {
+      current += char;
+    }
+  }
+  cells.push(current);
+  return cells;
+}
+
+/**
+ * Convert CSV text into a GitHub-flavored markdown table.
+ * The first non-empty line becomes the header row; ragged rows are padded with
+ * empty cells; pipes inside cells are escaped so the table stays valid.
+ * @param {string} csvText - Raw CSV text.
+ * @returns {string} Markdown table, or '' when there is nothing to convert.
+ */
+function csvToMarkdownTable(csvText) {
+  if (typeof csvText !== 'string' || csvText.trim().length === 0) return '';
+
+  const rows = csvText
+    .split(/\r?\n/)
+    .filter((line) => line.trim().length > 0)
+    .map((line) => parseCsvLine(line));
+  if (rows.length === 0) return '';
+
+  const columnCount = Math.max(...rows.map((row) => row.length));
+  const paddedRows = rows.map((row) => {
+    const cells = row.map((cell) => cell.trim().replace(/\|/g, '\\|'));
+    while (cells.length < columnCount) cells.push('');
+    return cells;
+  });
+
+  const formatRow = (cells) => `| ${cells.join(' | ')} |`;
+  const separator = `|${'---|'.repeat(columnCount)}`;
+
+  const [header, ...dataRows] = paddedRows;
+  return [formatRow(header), separator, ...dataRows.map(formatRow)].join('\n');
+}
+
+module.exports = { csvToMarkdownTable, parseCsvLine };