rollup.config.js

// import babel from 'rollup-plugin-babel';
// import resolve from 'rollup-plugin-node-resolve';
// import commonjs from 'rollup-plugin-commonjs';
import babel from '@rollup/plugin-babel';
import { terser } from 'rollup-plugin-terser';
import babelrc from './.babelrc.json';

function glsl() {
  return {
    transform( code, id ) {
      if ( /\.glsl$/.test( id ) === false ) return;

      var transformedCode = 'export default ' + JSON.stringify(
          code
            .replace( /[ \t]*\/\/.*\n/g, '' ) // remove //
            .replace( /[ \t]*\/\*[\s\S]*?\*\//g, '' ) // remove /* */
            .replace( /\n{2,}/g, '\n' ) // # \n+ to \n
        ) + ';';
      return {
        code: transformedCode,
        map: { mappings: '' }
      };
    }
  };
}

export default [
	{
		input: 'src/main.js',
    external: ['three'],
		plugins: [
			glsl(),
			babel( {
        exclude: ['node_modules/**', 'src/**/*.glsl'],
				babelHelpers: 'bundled',
				compact: false,
				babelrc: false,
				...babelrc
			} )
		],
		output: [
			{
				format: 'umd',
        globals: {
          three: 'THREE'
        },
				name: 'BAS',
				file: 'dist/bas.js',
				indent: '\t'
			}
		]
	},
	{
		input: 'src/main.js',
    external: ['three'],
		plugins: [
			glsl(),
			babel( {
        exclude: ['node_modules/**', 'src/**/*.glsl'],
				babelHelpers: 'bundled',
				babelrc: false,
				...babelrc
			} ),
			terser(),
		],
		output: [
			{
				format: 'umd',
        globals: {
          three: 'THREE'
        },
				name: 'BAS',
				file: 'dist/bas.min.js'
			}
		]
	},
	{
		input: 'src/main.js',
    external: ['three'],
		plugins: [
			glsl(),
		],
		output: [
			{
				format: 'esm',
        globals: {
          three: 'THREE'
        },
				file: 'dist/bas.module.js'
			}
		]
	}
];


// export default {
//   plugins: [
//     babel({
//       exclude: ['node_modules/**', 'src/**/*.glsl'],
//     }),
//     resolve({
//       jsnext: true,
//       main: true,
//       browser: true,
//     }),
//     commonjs(),
//     glsl()
//   ],
//   input: 'src/main.js',

//   external: ['three'],
//   globals: {
//     three: 'THREE'
//   },

//   output: [
//     {
//       format: 'umd',
//       name: 'BAS',
//       file: 'dist/bas.js'
//     },
//     {
//       format: 'es',
//       file: 'dist/bas.module.js'
//     }
//   ],
// };