rollup.config.js

import resolve from '@rollup/plugin-node-resolve'
import commonjs from '@rollup/plugin-commonjs'
import typescript from 'rollup-plugin-typescript2'
import alias from '@rollup/plugin-alias'
import excludeDependenciesFromBundle from 'rollup-plugin-exclude-dependencies-from-bundle'
import bundleSize from 'rollup-plugin-bundle-size'
import pkg from './package.json'

export default [
  // browser-friendly UMD build
  {
    input: 'src/index.ts',
    plugins: [
      resolve(), // so Rollup can find `ms`
      commonjs(), // so Rollup can convert `ms` to an ES module
      typescript({
        typescript: require('typescript'),
      }), // so Rollup can convert TypeScript to JavaScript
      alias({
        resolve: ['.ts', '.js', '.tsx', '.jsx'],
        entries: [{ find: '@/', replacement: './src/' }],
      }),
      // exclude dependencies and peerDependencies
      excludeDependenciesFromBundle({
        peerDependencies: true,
      }),
      // console.log bundle file size
      bundleSize(),
    ],
    output: {
      name: 'dayjs-plugin-template',
      file: pkg.browser,
      format: 'umd',
    },
  },

  // CommonJS (for Node) and ES module (for bundlers) build.
  // (We could have three entries in the configuration array
  // instead of two, but it's quicker to generate multiple
  // builds from a single configuration where possible, using
  // an array for the `output` option, where we can specify
  // `file` and `format` for each target)
  {
    input: 'src/index.ts',
    external: ['ms'],
    plugins: [
      typescript(), // so Rollup can convert TypeScript to JavaScript
      alias({
        resolve: ['.ts', '.js', '.tsx', '.jsx'],
        entries: [{ find: '@/', replacement: './src/' }],
      }),
      bundleSize(),
    ],
    output: [
      { file: pkg.main, format: 'cjs', exports: 'default' },
      { file: pkg.module, format: 'es', exports: 'default' },
    ],
  },
]