rollup.config.js

import terser from '@rollup/plugin-terser';
import resolve from '@rollup/plugin-node-resolve';
import commonjs from '@rollup/plugin-commonjs';

import pkg from './package.json';

const srcEntry = pkg.source;
const umdDist = pkg[ 'umd:main' ];
const umdName = 'DiagramJSGrid';

function pgl(plugins = []) {
  return plugins;
}

export default [

  // browser-friendly UMD build
  {
    input: srcEntry,
    output: {
      file: umdDist.replace(/\.js$/, '.prod.js'),
      format: 'umd',
      name: umdName
    },
    plugins: pgl([
      resolve(),
      commonjs(),
      terser()
    ])
  },
  {
    input: srcEntry,
    output: {
      file: umdDist,
      format: 'umd',
      name: umdName
    },
    plugins: pgl([
      resolve(),
      commonjs()
    ])
  },
  {
    input: srcEntry,
    output: [
      { file: pkg.main, format: 'cjs', exports: 'default' },
      { file: pkg.module, format: 'es', exports: 'default' }
    ],
    external: [
      'diagram-js/lib/features/grid-snapping/GridUtil',
      'diagram-js/lib/layout/LayoutUtil',
      'min-dom',
      'tiny-svg'
    ],
    plugins: pgl()
  }
];