perf: only import JSZip when needed (bundle splitting) (openedx#1933)

Author: bradenmacdonald

src/files-and-videos/files-page/FilesPage.test.jsx

@@ -358,7 +358,9 @@ describe('FilesAndUploads', () => {
 
         global.fetch = jest.fn().mockImplementation(() => mockFetchResponse);
         fireEvent.click(downloadButton);
-        expect(fetch).toHaveBeenCalledTimes(2);
+        await waitFor(() => {
+          expect(global.fetch).toHaveBeenCalledTimes(2);
+        });
       });
 
       it('sort button should be enabled and sort files by name', async () => {

src/files-and-videos/files-page/data/api.js

@@ -1,7 +1,6 @@
 import { camelCaseObject, ensureConfig, getConfig } from '@edx/frontend-platform';
 import { getAuthenticatedHttpClient } from '@edx/frontend-platform/auth';
 
-import JSZip from 'jszip';
 import saveAs from 'file-saver';
 
 ensureConfig([
@@ -39,11 +38,13 @@ export async function getAssetDetails({ courseId, filenames, fileCount }) {
 /**
  * Fetch asset file.
  * @param {blockId} courseId Course ID for the course to operate on
-
  */
 export async function getDownload(selectedRows, courseId) {
   const downloadErrors = [];
   if (selectedRows?.length > 1) {
+    // Don't import JSZip until/unless we need it, to bundle multiple files into one download.
+    // This helps keep the main Authoring MFE bundle size smaller.
+    const JSZip = (await import('jszip')).default;
     const zip = new JSZip();
     const date = new Date().toString();
     const folder = zip.folder(`${courseId}-assets-${date}`);