add shared table column width normalizer for imports

2026-05-20 00:14:10 +08:00 · 2026-04-22 00:51:42 +01:00
parent 00e8c53852
commit c5e9be6b36
1 changed files with 94 additions and 0 deletions
@@ -0,0 +1,94 @@
+import { CheerioAPI, Cheerio } from 'cheerio';
+
+/**
+ * Extracts a pixel-integer width from either the `width` attribute or
+ * `style="width: Npx"` on a <col>/<td>/<th>. Returns null when absent,
+ * non-numeric, or a non-px unit (em, %).
+ */
+function parsePixelWidth(el: Cheerio<any>): number | null {
+  const attr = el.attr('width');
+  if (attr) {
+    const n = parseInt(attr, 10);
+    if (Number.isFinite(n) && n > 0) return n;
+  }
+  const style = el.attr('style') || '';
+  const m = style.match(/(?:^|;)\s*width\s*:\s*([\d.]+)\s*px/i);
+  if (m) {
+    const n = parseInt(m[1], 10);
+    if (Number.isFinite(n) && n > 0) return n;
+  }
+  return null;
+}
+
+/**
+ * Derives per-column widths for a table, in visual column order.
+ * Priority: <colgroup><col> → first-row cells' own width style.
+ * Returns an array of length = number of columns, with null entries
+ * for columns whose width couldn't be determined.
+ */
+function deriveColumnWidths(
+  $: CheerioAPI,
+  table: Cheerio<any>,
+): (number | null)[] | null {
+  const cols = table.find('> colgroup > col');
+  if (cols.length > 0) {
+    const widths: (number | null)[] = [];
+    cols.each(function () {
+      widths.push(parsePixelWidth($(this)));
+    });
+    if (widths.some((w) => w !== null)) return widths;
+  }
+
+  // Fallback: first row's cells.
+  const firstRow = table.find('> tbody > tr, > thead > tr, > tr').first();
+  if (!firstRow.length) return null;
+
+  const widths: (number | null)[] = [];
+  firstRow.children('td, th').each(function () {
+    const cell = $(this);
+    const colspan = parseInt(cell.attr('colspan') || '1', 10) || 1;
+    const w = parsePixelWidth(cell);
+    for (let i = 0; i < colspan; i++) {
+      widths.push(w !== null ? Math.round(w / colspan) : null);
+    }
+  });
+  if (widths.every((w) => w === null)) return null;
+  return widths;
+}
+
+/**
+ * Apply colwidth attributes to the first row of each table based on
+ * derived column widths. Accounts for colspan. Idempotent — re-running
+ * on already-normalized markup is a no-op.
+ *
+ * This lives upstream of tiptap's generateJSON: tiptap reads
+ * `colwidth="N[,N...]"` on <td>/<th> to build the runtime <colgroup>.
+ */
+export function normalizeTableColumnWidths(
+  $: CheerioAPI,
+  $root: Cheerio<any>,
+): void {
+  $root.find('table').each(function () {
+    const table = $(this);
+    const colWidths = deriveColumnWidths($, table);
+    if (!colWidths) return;
+
+    const firstRow = table.find('> tbody > tr, > thead > tr, > tr').first();
+    if (!firstRow.length) return;
+
+    let col = 0;
+    firstRow.children('td, th').each(function () {
+      const cell = $(this);
+      if (cell.attr('colwidth')) {
+        col += parseInt(cell.attr('colspan') || '1', 10) || 1;
+        return;
+      }
+      const colspan = parseInt(cell.attr('colspan') || '1', 10) || 1;
+      const slice = colWidths.slice(col, col + colspan);
+      col += colspan;
+      if (slice.length === 0 || slice.every((w) => w === null)) return;
+      const values = slice.map((w) => (w == null ? 100 : w));
+      cell.attr('colwidth', values.join(','));
+    });
+  });
+}