Why Manual File Copying Is Required in React PDF Viewer

14 Aug 20261 minute to read

The PDF Viewer supports multiple build systems and can work without a bundler by referencing assets directly using HTML tags. To keep load times efficient, the library is split into smaller modules and uses lazy loading for certain assets.

• The primary entry point, “pdfium.js”, is typically included by bundlers automatically.
• Additional resources under “ej2-pdfviewer-lib” are loaded on demand at runtime. Because the host app does not know about these lazy-loaded files, they are not automatically emitted by bundlers or available to static servers unless they are copied and referenced.

When not using a bundler, or when the bundler does not emit these assets, copy the required files from node_modules to a web-accessible path in your app (for example, src/ej2-pdfviewer-lib) and reference them accordingly. This ensures the viewer can fetch the lazy-loaded assets when needed and prevents runtime 404 errors.

If the bundler is configured to emit static assets from node_modules, verify that the build output contains the necessary files from @syncfusion/ej2-pdfviewer/dist/ej2-pdfviewer-lib and that your app serves them from a public path. Otherwise, perform a manual or scripted copy step during your build process.