Check if a document contains annotations

To check if a document contains annotations, use Instance#getAnnotations to retrieve the annotations for each page. Then, flatten the array and evaluate the resulting array to see whether or not it’s empty:

PSPDFKit.load({
  // Your configuration.
}).then(async (instance) => {
  const pagesAnnotations = await Promise.all(
    Array.from({
      length: instance.totalPageCount
    }).map((_, pageIndex) => instance.getAnnotations(pageIndex))
  );

  const allAnnotations = pagesAnnotations
    .map((pageList) => pageList.toJS())
    .flat();

  const hasAnnotations = allAnnotations.length > 0;
});

This has been tested with Nutrient Web SDK 2020.5.1.