Update the examples/-folder to account for outputting of JavaScript modules (PR 17055 follow-up)

This patch also changes most examples to use "top level await", since that's now supported and slightly simplifies the code.

examples/components/pageviewer.mjs

@@ -0,0 +1,63 @@
+/* Copyright 2014 Mozilla Foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+if (!pdfjsLib.getDocument || !pdfjsViewer.PDFPageView) {
+  // eslint-disable-next-line no-alert
+  alert("Please build the pdfjs-dist library using\n  `gulp dist-install`");
+}
+
+// The workerSrc property shall be specified.
+//
+pdfjsLib.GlobalWorkerOptions.workerSrc =
+  "../../node_modules/pdfjs-dist/build/pdf.worker.mjs";
+
+// Some PDFs need external cmaps.
+//
+const CMAP_URL = "../../node_modules/pdfjs-dist/cmaps/";
+const CMAP_PACKED = true;
+
+const DEFAULT_URL = "../../web/compressed.tracemonkey-pldi-09.pdf";
+const PAGE_TO_VIEW = 1;
+const SCALE = 1.0;
+
+const ENABLE_XFA = true;
+
+const container = document.getElementById("pageContainer");
+
+const eventBus = new pdfjsViewer.EventBus();
+
+// Loading document.
+const loadingTask = pdfjsLib.getDocument({
+  url: DEFAULT_URL,
+  cMapUrl: CMAP_URL,
+  cMapPacked: CMAP_PACKED,
+  enableXfa: ENABLE_XFA,
+});
+
+const pdfDocument = await loadingTask.promise;
+// Document loaded, retrieving the page.
+const pdfPage = await pdfDocument.getPage(PAGE_TO_VIEW);
+
+// Creating the page view with default parameters.
+const pdfPageView = new pdfjsViewer.PDFPageView({
+  container,
+  id: PAGE_TO_VIEW,
+  scale: SCALE,
+  defaultViewport: pdfPage.getViewport({ scale: SCALE }),
+  eventBus,
+});
+// Associate the actual page with the view, and draw it.
+pdfPageView.setPdfPage(pdfPage);
+pdfPageView.draw();