rollup.config.browser.js

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

const name = 'brain';
const extensions = ['.js', '.json', '.node', '.ts'];
const file = 'dist/browser.js';

export default {
  input: './src/index.ts',

  // Specify here external modules which you don't want to include in your bundle (for instance: 'lodash', 'moment' etc.)
  // https://rollupjs.org/guide/en#external-e-external
  external: ['gpu.js'],

  plugins: [
    // Allows node_modules resolution
    resolve({
      preferBuiltins: false,
      browser: true,
      extensions,
    }),

    // allow json importing
    json(),

    // Allow bundling cjs modules. Rollup doesn't understand cjs
    commonjs(),

    // Compile TypeScript/JavaScript files
    typescript(),
  ],
  output: [
    {
      file,
      format: 'umd',
      sourcemap: true,
      globals: {
        'gpu.js': `GPU`,
      },
      name,
    },
  ],
};