rollup.config.ts

import babel from 'rollup-plugin-babel'
import nodeResolve from 'rollup-plugin-node-resolve'
import commonjs from 'rollup-plugin-commonjs'
import json from 'rollup-plugin-json'
import builtins from 'rollup-plugin-node-builtins'
import globals from 'rollup-plugin-node-globals'
import typescript from 'rollup-plugin-typescript2'

// Require understands JSON files.
const pkg = require('./package.json')

const input = 'src/client.ts'
const name = 'client'

const replaceMinJsExtension = filename => filename.replace('.min.js', '.js')

// External dependencies tell Rollup "it's ok that you can't resolve these modules;
// don't try to bundle them but rather leave their import statements in place"
const external = [
  'axios',
  'http', // imported by axios
  'https', // imported by axios
  'url', // imported by follow-redirects
  'assert', // imported by follow-redirects
  'stream', // imported by follow-redirects
  'tty', // imported by follow-redirects
  'util', // imported by follow-redirects
  'zlib' // imported by axios
]

const globalDependencies = {}

const plugins = [
  typescript({ useTsconfigDeclarationDir: true }),
  // Node modules resolution
  nodeResolve({
    extensions: ['.js', '.jsx'],
    browser: true
  }),

  // Let's transpile our own ES6 code into ES5
  babel({ exclude: 'node_modules/**' }),

  // Most packages in node_modules are legacy CommonJS, so let's convert them to ES
  commonjs(),

  json({
    exclude: 'node_modules/**',
    preferConst: true,
    indent: '  '
  }),
  globals(),
  builtins()
]

// browser-friendly UMD build
const configUMD = {
  input,
  sourcemap: true,
  output: {
    name,
    file: replaceMinJsExtension(pkg.browser),
    format: 'umd'
  },
  name,
  plugins,
  external,
  globals: globalDependencies
}

// 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)
const configCjsAndEs = {
  input,
  sourcemap: true,
  output: [
    {
      file: replaceMinJsExtension(pkg.main),
      format: 'cjs'
    },
    {
      file: replaceMinJsExtension(pkg.module),
      format: 'es'
    }
  ],
  plugins,
  external,
  globals: globalDependencies
}

export default [configUMD, configCjsAndEs]