post-build.js

import { writeFile, copyFile } from 'fs/promises'
import path from 'path'
import packageJSON from './package.json' with { type: 'json' }
 
async function writePackageJSON() {
  const packageJSONData = {
    name: packageJSON.name,
    version: packageJSON.version,
    description: packageJSON.description,
    author: packageJSON.author,
    license: packageJSON.license,
    repository: packageJSON.repository,
    keywords: packageJSON.keywords,
    sideEffects: false,
    main: "./index.js",
    module: "./index.js",
    types: "./index.d.ts",
    unpkg: "./index.umd.js",
    jsdelivr: "./index.umd.js",
    exports: {
      ".": {
        "import": {
          "types": "./index.d.ts",
          "default": "./index.js"
        },
        "script": "./index.umd.js"
      }
    },
    peerDependencies: packageJSON.peerDependencies,
    files: ["*"]
  }
 
  const packageJSONPath = path.resolve('./', 'dist', 'package.json')
  await writeFile(
    packageJSONPath,
    JSON.stringify(packageJSONData, null, 2),
    { encoding: 'utf-8' }
  )
}
 
async function copyReadme() {
  const sourceReadme = path.resolve('./', 'README.md')
  const destReadme = path.resolve('./', 'dist', 'README.md')
  await copyFile(sourceReadme, destReadme)
}
 
async function copyLicense() {
  const sourceLicense = path.resolve('./', 'LICENSE')
  const destLicense = path.resolve('./', 'dist', 'LICENSE')
  await copyFile(sourceLicense, destLicense)
}
 
async function postBuild() {
  await Promise.all([
    writePackageJSON(),
    copyReadme(),
    copyLicense()
  ])
}
 
postBuild()