mozilla/pdf.js · error · FormatError

Page dictionary kid reference points to wrong type of object

Error message

Page dictionary kid reference points to wrong type of object.

What it means

Thrown in Catalog.getPageDict() (catalog.js:1379) when a node popped off nodesToVisit is neither a Ref nor a Dict. Kids entries should be Refs (resolving to Dicts); after a Ref resolves to a non-Dict it is pushed back and re-examined here. If that object is still not a Dict, the kid reference is the wrong type.

Source

Thrown at src/core/catalog.js:1379

            // Help improve performance of the `getPageIndex` method.
            if (!pageIndexCache.has(currentNode)) {
              pageIndexCache.put(currentNode, currentPageIndex);
            }

            if (currentPageIndex === pageIndex) {
              return [obj, currentNode];
            }
            currentPageIndex++;
            continue;
          }
        }
        nodesToVisit.push(obj);
        continue;
      }

      // Must be a child page dictionary.
      if (!(currentNode instanceof Dict)) {
        throw new FormatError(
          "Page dictionary kid reference points to wrong type of object."
        );
      }
      const { objId } = currentNode;

      let count = currentNode.getRaw("Count");
      if (count instanceof Ref) {
        count = await xref.fetchAsync(count);
      }
      if (Number.isInteger(count) && count >= 0) {
        // Cache the Kids count, since it can reduce redundant lookups in
        // documents where all nodes are found at *one* level of the tree.
        if (objId && !pageKidsCountCache.has(objId)) {
          pageKidsCountCache.put(objId, count);
        }

        // Skip nodes where the page can't be.
        if (currentPageIndex + count <= pageIndex) {

View on GitHub (pinned to 5903d58d58)

Solutions

1. Repair the PDF with qpdf/mutool to rebuild /Kids as proper indirect references to dictionaries.
2. Validate the page tree with 'qpdf --check' before relying on getPage().
3. Load with error recovery enabled and accept that the affected page may be unreachable.
4. If producing PDFs, ensure every /Kids entry is an indirect reference to a /Page or /Pages dictionary.

// Pre-validation requires walking the page tree, which is the failing operation.
// Repair the PDF instead: mutool clean in.pdf out.pdf

try {
  const page = await pdf.getPage(n);
} catch (err) {
  if (/kid reference points to wrong type/i.test(err?.message)) {
    console.warn('Malformed /Kids entry; repair the PDF', err);
  } else throw err;
}

When it happens

Trigger: A Kids array entry is a non-Ref primitive (number/string/null) and is not a Dict, OR a Ref resolves to a non-dictionary object (stream, array, scalar). Reached during pdfDocument.getPage(n) traversal.

Common situations: Corrupt PDF with a malformed /Kids array containing scalar/null entries; a Ref pointing at the wrong (non-dict) object due to a shifted xref; a hand-edited page tree.

Related errors

• Node must be a dictionary.
• Pages tree contains circular reference.
• Page dictionary kids object is not an array.
• Page index ${pageIndex} not found.
• The reference does not point to a /Page dictionary.

AI-assisted analysis of mozilla/pdf.js@5903d58d58 (2026-08-13). Data as JSON: /api/errors/e28a29fc65f157b8. Report an issue: GitHub.