urbit/pkg/npm/api/rollup.config.ts

import { nodeResolve } from '@rollup/plugin-node-resolve';
import commonJS from '@rollup/plugin-commonjs';
import { terser } from 'rollup-plugin-terser';
import babel from '@rollup/plugin-babel';
import typescript from 'rollup-plugin-typescript2';
import analyze from 'rollup-plugin-analyzer'

const input = ['./index.ts'];

// Skip certain warnings
function onwarn(warning) {
  if (warning.code === 'THIS_IS_UNDEFINED') {
    return;
  }

  console.warn(warning.message);
}

export default [
  {
    input,
    onwarn,
    plugins: [
      nodeResolve({
        extensions: ['.js', '.jsx', '.ts', '.tsx']
      }),
      commonJS(),
      typescript(),
      babel({
        babelHelpers: 'bundled',
        exclude: ['node_modules/**']
      }),
      terser({
        ecma: 2017,
        compress: true,
        mangle: true
      })
    ],
    output: {
      file: 'dist/urbit-api.min.js',
      format: 'umd',
      name: 'UrbitAPI', // this is the name of the global object
      esModule: false,
      exports: 'named',
      sourcemap: true
    }
  },
  {
    input,
    onwarn,
    plugins: [
      nodeResolve({
        extensions: ['.js', '.jsx', '.ts', '.tsx']
      }),
      commonJS(),
      typescript(),
      analyze({
        limit: 10
      })
    ],
    output: [
      {
        dir: 'dist/esm',
        format: 'esm',
        exports: 'named',
        sourcemap: true
      },
      {
        dir: 'dist/cjs',
        format: 'cjs',
        exports: 'named',
        sourcemap: true
      }
    ]
  }
];