Pdf.js: Could not be cloned

[StardustProducts]

I unfortunately can't upload the PDF because I don't have authorization to do so in my massive bureaucracy.

Web browser: Chrome 58.0.3029.110 (64-bit)
Windows 10
PDF.js version 1.8.188 (although main fails as well)

Background; I am using the library to extract the contents of form fields (getAnnotations()), and NOT to display the document in the browser. The gist of the problem is that a call to page.getAnnotation() fails when there is a form field (such as in my case a signature block) that can't be serialized. It throws an exception deep in util.js and abandons the whole call to page.getAnnotation() as below;

:8888/src/shared/util.js:1301 

Uncaught (in promise) DataCloneError: Failed to execute 'postMessage' on 'DedicatedWorkerGlobalScope': function NetworkManager_getXhr() {
        return new XMLHttpRequest();
      } could not be cloned.

I tried catching the exception in my code by wrapping the call to page.getAnnotations() in a try catch, but it doesn't seem to work. It does work to comment out that block of code.

If someone could tell me how to just ignore problematic fields/annotations this would be a wonderful solution.

'use strict';

// In production, the bundled pdf.js shall be used instead of SystemJS.
Promise.all([SystemJS.import('pdfjs/display/api'),
             SystemJS.import('pdfjs/display/global')])
       .then(function (modules) {
  var api = modules[0], global = modules[1];
  // In production, change this to point to the built `pdf.worker.js` file.
  global.PDFJS.verbosity=global.PDFJS.VERBOSITY_LEVELS.infos;
  global.PDFJS.workerSrc = '../../src/worker_loader.js';

  // Fetch the PDF document from the URL using promises.
  api.getDocument('myDocument.pdf').then(function (pdf) {
    // Fetch the page.
    var numPages = pdf.numPages;
    var myResult="";
    function myCallback(pageNumber, text) {
        //alert("processing page "+pageNumber+", text="+text);
        document.getElementById("myFormDiv").innerHTML+=text;
    }
    for (var pageNum = 1; pageNum<=numPages; pageNum++) {
        function doit(currentPageNumber) {
            //alert("processing page "+currentPageNumber);
            var response="<h1>Page "+currentPageNumber+"</h1>\n";
            pdf.getPage(currentPageNumber).then(function (page) {

                function escapeHtml(unsafe) {
                    if (typeof unsafe !== 'string') { return ""; }
                    return unsafe.replace(/&/g, "&amp;").replace(/</g, "&lt;").replace(/>/g, "&gt;").replace(/"/g, "&quot;").replace(/'/g, "&#039;");
                }

                //attempt to read the data!!!!
                page.getAnnotations().then(function(items) {
                    console.log(items); //Dump this into the console to see what properties are available for each field                
                    items.forEach(function(item) {
                        response+="<div>"+escapeHtml(item.alternativeText)+":"+escapeHtml(item.fieldValue)+"<div>\n";
                    });
                    myCallback(currentPageNumber, response);            
                }); //end getAnnotations()

            }); //end getPage()

            return response;
        } //end doit()
        doit(pageNum);
    }//end iterating pages
  }); //end getDocument()
});

[StardustProducts]

Problem solved with the following added line... I just had to state my intention.

            var parameters = { intent: 'display' };
            page.getAnnotations(parameters).then(function(items) {