Preloading WebViewer library/worker files

When WebViewer is loaded with the initialDoc option, it will first load the large library resources, like PDF or Office workers, depending on the type of file you are trying to open, and then the file will be processed and displayed on the screen.

By default WebViewer will load the worker files lazily when needed but if WebViewer needs to be initialized without opening a file or if you will be loading both PDF and Office files, you can use the preloadWorker option to load the workers up front.

WebViewer({
  path: '../../../lib',
  preloadWorker: 'pdf',
  ...
}, document.getElementById('viewer'))
  .then(instance => {
      // ...
  });

Here WebViewer is displayed without opening a file but the PDF workers have still been loaded.

The MS Office workers are preloaded in the same way as PDF workers, you only need to change the preloadWorker option to "office". If you decide to preload both PDF and Office workers on the initial load change it to "all".

WebViewer({
  path: '../../../lib',
  preloadWorker: 'office', // 'all' to preload both pdf & office workers
  ...
}, document.getElementById('viewer'))
  .then(instance => {
      // ...
  });