rollup.config.js

import commonjs from '@rollup/plugin-commonjs';
import resolve from '@rollup/plugin-node-resolve';
import nodePolyfills from 'rollup-plugin-polyfill-node';
import copy from 'rollup-plugin-copy';
import ignore from 'rollup-plugin-ignore';

/**
 * # Rollup configuration
 *
 * ### pdf.js
 *
 * - Transform UMD to ESM
 * - Resolve commonJS imports, **except**:
 * - Ignore `pdf.worker.js` import. This is very important, as it's conditionally required and is very large in size.
 * - Copy over all remaining files we wish to provide.
 *
 * With `pdf.worker.js` ignored, pdfjs will expect a link to the file externally (see above)
 *
 * ### pdf_viewer.js
 *
 * - Transform UMD to ESM
 * - Resolve imports
 * - Ignore `pdf.js`. This is important, as we don't want to serve duplicates of pdfjs.
 *
 * With `pdf.js` ignored, the viewer will expect to find a global pdfjs. This is circumvented by temporarily adding pdfjs to the global scope,
 * and removed immediately after the viewer acquires a reference.
 */

export default [
  {
    input: './src/core/pdf.cjs',
    output: {
      file: './build/pdf.js',
      format: 'es',
    },
    plugins: [
      ignore(['./pdf.worker.js']),
      resolve({
        browser: true,
        preferBuiltins: false,
      }),
      commonjs(),
      copy({
        targets: [
          // the worker is used directly as-is
          {
            src: './node_modules/pdfjs-dist/build/pdf.worker.js',
            dest: './build/',
          },
          {
            src: './node_modules/pdfjs-dist/build/pdf.worker.min.js',
            dest: './build/',
          },
          {
            src: './node_modules/pdfjs-dist/build/pdf.worker.entry.js',
            dest: './build/',
          },
          {
            src: './node_modules/pdfjs-dist/build/pdf.worker.js.map',
            dest: './build/',
          },
          {
            src: './node_modules/pdfjs-dist/LICENSE',
            dest: './',
          },
          // vend typings
          {
            src: './src/pdf.d.ts',
            dest: './build/',
          },
          {
            src: './node_modules/pdfjs-dist/types/',
            dest: './',
          },
        ],
      }),
      nodePolyfills(),
    ],
  },
  {
    input: './src/viewer/module.cjs',
    output: {
      file: './web/module.js',
      format: 'es',
    },
    plugins: [
      ignore(['../build/pdf.js']),
      resolve({
        browser: true,
        preferBuiltins: false,
      }),
      commonjs(),
      copy({
        targets: [
          {
            src: './src/viewer/pdf_viewer.js',
            dest: './web/',
          },
          {
            src: './src/viewer/util.js',
            dest: './web/',
          },
          {
            src: './src/pdf_viewer.d.ts',
            dest: './web/',
          },
        ],
      }),
      nodePolyfills(),
    ],
  },
];