This regressed in commit acdd49f480, i.e. PR 6571. Fixes 6957.
acdd49f480
@ -480,6 +480,10 @@ var WorkerMessageHandler = PDFJS.WorkerMessageHandler = {
var workerHandlerName = docParams.docId + '_worker';
var handler = new MessageHandler(workerHandlerName, docId, port);
// Ensure that postMessage transfers are correctly enabled/disabled,
// to prevent "DataCloneError" in older versions of IE (see issue 6957).
handler.postMessageTransfers = docParams.postMessageTransfers;
function ensureNotTerminated() {
if (terminated) {
throw new Error('Worker was terminated');
@ -454,7 +454,8 @@ function _fetchDocument(worker, source, pdfDataRangeTransport, docId) {
cMapPacked: PDFJS.cMapPacked,
disableFontFace: PDFJS.disableFontFace,
disableCreateObjectURL: PDFJS.disableCreateObjectURL,
verbosity: PDFJS.verbosity
verbosity: PDFJS.verbosity,
postMessageTransfers: PDFJS.postMessageTransfers,
}).then(function (workerId) {
if (worker.destroyed) {
throw new Error('Worker was destroyed');