now-cli/lib/utils/check-path.js

// Native
import os from 'os'
import path from 'path'

// Ours
import {error} from '../error'

export default async dir => {
  if (!dir) {
    return
  }

  const home = os.homedir()
  let location

  const paths = {
    home,
    desktop: path.join(home, 'Desktop'),
    downloads: path.join(home, 'Downloads')
  }

  for (const locationPath in paths) {
    if (!{}.hasOwnProperty.call(paths, locationPath)) {
      continue
    }

    if (dir === paths[locationPath]) {
      location = locationPath
    }
  }

  if (!location) {
    return
  }

  let locationName

  switch (location) {
    case 'home':
      locationName = 'user directory'
      break
    case 'downloads':
      locationName = 'downloads directory'
      break
    default:
      locationName = location
  }

  error(`You're trying to deploy your ${locationName}.`)
  process.exit(1)
}