make-package.js

const { resolve } = require("path")
const { ncp } = require("ncp")
const package = require("./package.json")
const fs = require("fs")

middleware(makePackageJson, copyReadme, copyCli)()

function makePackageJson(next) {
  const dest = resolve(__dirname, "./dist/package/package.json")
  const content = Object.assign({}, package, {
    main: "umd/index.js",
    module: "es/index.js",
    typings: "lib/index.d.ts"
  })
  fs.writeFileSync(dest, JSON.stringify(content, null, 2), "utf8")
  next()
}

function copyReadme(next) {
  const src = resolve(__dirname, "./README.md")
  const dest = resolve(__dirname, "./dist/package/README.md")
  ncp(src, dest, err => {
    if (err) throw err
    next()
  })
}

function copyCli(next) {
  const src = resolve(__dirname, "./cli")
  const dest = resolve(__dirname, "./dist/package/cli")
  ncp(src, dest, err => {
    if (err) throw err
    next()
  })
}

function done() {
  console.log("Done!")
}

function middleware(...fns) {
  return (...args) => {
    return fns.reduceRight((next, fn) => () => fn(next, ...args), () => {})()
  }
}