Extracting pages from PDF using JavaScript

If the user only wants to download part of a document, the extractPages function can be used to download specific pages. For example:

WebViewer(...)
  .then(instance => {
    const { documentViewer, annotationManager } = instance.Core;

    documentViewer.addEventListener('documentLoaded', async () => {
      const doc = documentViewer.getDocument();
      const pagesToExtract = [2, 3];

      // only include annotations on the pages to extract
      const annotList = annotationManager.getAnnotationsList().filter(annot => pagesToExtract.indexOf(annot.PageNumber) > -1);
      const xfdfString = await annotationManager.exportAnnotations({ annotList });
      const data = await doc.extractPages(pagesToExtract, xfdfString);
      const arr = new Uint8Array(data);

      //optionally save the blob to a file or upload to a server
      const blob = new Blob([arr], { type: 'application/pdf' });
    });
  });