unbundle/bin.js

import/export & node_modules in the browser, without the bundling

#!/usr/bin/env node

const unbundle = require('./unbundle')
const yargs = require('yargs')
const chalk = require('chalk')
const {
  constants: { COPYFILE_EXCL },
  promises: { writeFile, mkdir, copyFile }
} = require('fs')
const { resolve, dirname, relative, join } = require('path')

async function main () {
  const { argv } = yargs
    .option('entry', {
      type: 'string',
      alias: 'i',
      demandOption: true,
      describe: 'File path of source code entry point'
    })
    .option('destination', {
      type: 'string',
      alias: 'o',
      demandOption: true,
      describe: 'Directory path to write output'
    })
    .option('root', {
      type: 'string',
      describe: 'Prefix path for `node_modules`',
      default: '/'
    })
    .option('force', {
      type: 'boolean',
      alias: 'f',
      describe: 'Overwrite existing files',
      default: false
    })
    .option('recurse', {
      type: 'boolean',
      alias: 'r',
      describe: 'Recursively trace all files',
      default: true
    })
    .option('verbose', {
      type: 'boolean',
      describe: 'Show more information during file processing',
      default: false
    })
    .example('--entry ./src/app.js --destination ./dist')
    .example('Trace all dependencies of app.js and output to dist directory.')
    .example('')
    .example('--entry index.js --destination public/assets/scripts --root /assets/scripts/')
    .example('Prefix imports of NPM packages with: /assets/scripts/node_modules/')
    .version()
    .help()

  const destination = resolve(argv.destination)
  const files = unbundle(argv.entry, argv)
  await mkdir(destination, { recursive: true })
  for (const file of files.values()) {
    console.log(file.to)
    const to = join(destination, file.to)
    await mkdir(dirname(to), { recursive: true })
    try {
      await writeFile(to, file.code, { flag: argv.force ? 'w' : 'wx' })
      if (argv.verbose) console.log(`File: ${file.to}`)
      if (file.map) {
        const fromMap = resolve(dirname(file.from), file.map)
        const toMap = resolve(dirname(to), file.map)
        await mkdir(dirname(toMap), { recursive: true })
        await copyFile(fromMap, toMap, argv.force ? 0 : COPYFILE_EXCL)
        if (argv.verbose) console.log(`Map: ${relative(destination, toMap)}`)
      }
    } catch (error) {
      if (error.code === 'EEXIST') {
        throw new Error(
          `File exists at '${file.to}'. Use --force to overwrite.`
        )
      } else {
        throw error
      }
    }
  }
}

main()
  .catch((error) => {
    console.trace(chalk.red(error))
    process.exit(1)
  })