@tremorvideo/blink-cli/src/doctor/check-npm.js

const { promisify } = require('util')
const npmRoot = promisify(require('npm-root'))
const chalk = require('chalk')
const fs = require('fs-extra')
const { indent } = require('./indent-bullet')
const indent2 = indent.bind(null, 2)

const chownNpm = 'sudo chown -R `whoami` <npm dir path>'
const findNpmCmd = 'npm root -g'
const lsNpm = 'ls -ld <npm dir path>'
const noNpm = 'Currently cannot locate your npm global directory'
const findNpm = `Find your global npm node_modules directory with the following command:
  ${chalk.italic.gray(findNpmCmd)}`
const logNpmPerm = `Check permissions with the following command:
  ${chalk.italic.gray(lsNpm)}`
const npmPermissions = 'Check permissions for the npm global directory'
const fixNpmPerm = `If the user shows as 'root' and/or not your username, try the following:
  ${chalk.italic.gray(chownNpm)}
The permissions should match "drwxr-xr-x"`
const permFormat = `Output should resemble the following:
[permissions] [links] [user] ...`

module.exports = async () => {
  const warnings = []
  try {
    const npmPath = await npmRoot({ global: true })
    try {
      await fs.access(npmPath, fs.constants.R_OK | fs.constants.W_OK)
    } catch (err) {
      if (err.code === 'ENOENT') warnings.push(`${noNpm}\n${indent2(findNpm)}\n${indent2(logNpmPerm)}`)
      else if (err.code === 'EACCES') warnings.push(`${npmPermissions}\n${indent2(`${logNpmPerm.replace(/<.+>/, npmPath)}\n${permFormat}\n${fixNpmPerm.replace(/<.+>/, npmPath)}`)}`)
      else warnings.push(`${npmPermissions}\n${indent2(`${logNpmPerm.replace(/<.+>/, npmPath)}\n${permFormat}\n${fixNpmPerm.replace(/<.+>/, npmPath)}`)}`)
    }
  } catch (err) {
    warnings.push(`${noNpm}\n${indent2(findNpm)}`)
  }
  return { warnings, details: [] }
}