rollup.config.js

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 eslint from '@rollup/plugin-eslint';
import serve from 'rollup-plugin-serve';
import livereload from 'rollup-plugin-livereload';

const commonConfig = {
  input: 'src/index.ts',
  output: {
    name: 'contextBuilder',
    sourcemap: true,
  },
  plugins: [
    resolve({
      customResolveOptions: {
        moduleDirectories: ['node_modules'],
      },
    }),
    babel({
      exclude: 'node_modules/**',
      extensions: ['.js', '.jsx', '.es6', '.es', '.mjs', '.ts'],
      babelHelpers: 'runtime',
    }),
    commonjs({
      extensions: ['.js', '.ts'],
    }),
  ],
};

// ESM config
const esmConfig = Object.assign({}, commonConfig);
esmConfig.output = Object.assign({}, commonConfig.output, {
  file: 'dist/esm/contextBuilder.esm.js',
  format: 'esm',
});

// ESM prod config
const esmProdConfig = Object.assign({}, esmConfig);
esmProdConfig.output = Object.assign({}, esmConfig.output, {
  file: 'dist/esm/contextBuilder.esm.min.js',
  sourcemap: false,
});
esmProdConfig.plugins = [...esmConfig.plugins, terser()];

// UMD config
const umdConfig = Object.assign({}, commonConfig);
umdConfig.output = Object.assign({}, commonConfig.output, {
  file: 'dist/umd/contextBuilder.js',
  format: 'umd',
});
umdConfig.plugins = [...commonConfig.plugins];

// Production config
const umdProdConfig = Object.assign({}, umdConfig);
umdProdConfig.output = Object.assign({}, umdConfig.output, {
  file: 'dist/umd/contextBuilder.min.js',
  sourcemap: false,
});
umdProdConfig.plugins = [...umdConfig.plugins, terser()];

let configurations = [];
if (process.env.SERVE) {
  const serveConfig = Object.assign({}, commonConfig);
  serveConfig.input = 'render/index.ts';
  serveConfig.output = Object.assign({}, commonConfig.output, {
    file: 'dist/render/contextBuilder.iife.js',
    format: 'iife',
  });
  serveConfig.plugins = [
    eslint({
      exclude: ['node_modules/**', 'json/**'],
      throwOnError: true,
    }),
    ...umdConfig.plugins,
  ];
  serveConfig.plugins.push(
    serve({
      open: true,
      contentBase: ['dist'],
      host: 'localhost',
      port: '3030',
    }),
    livereload({
      watch: 'dist',
      verbose: false,
    })
  );
  configurations.push(serveConfig);
} else {
  configurations.push(esmConfig, esmProdConfig, umdConfig, umdProdConfig);
}

export default configurations;