index.js

// local development file
const envFile = './.env'

// load config for .env file - they are optional
const config = getConfig(envFile)

// will exit with error message when invalid!
validateToken(config)

// convert config into Hubot start
const params = convertConfigIntoParameters(config)
params.push('hubot')
params.push('--adapter')
params.push('slack')

// feed it to cross env - this will start Hubot with Slack
require('cross-env')(params)

function getConfig (envFile) {
  const fs = require('fs')

  if (fs.existsSync(envFile)) {
    return fs
      .readFileSync('./.env', 'utf-8')
      .split('\n') // thanks Windows!
      .filter(l => l && l.indexOf('=') !== -1 && l.indexOf('#') !== 0)
  }

  return ['ENVIRONMENT=production']
}

function validateToken (config) {
  const tokenStart = 'xoxb-'

  // check for Hubot token in config
  let token = config.find(c => c.indexOf('HUBOT_SLACK_TOKEN') === 0)
  if (token && token.indexOf('=') !== -1) return token.split('=')[1]
  else token = process.env.HUBOT_SLACK_TOKEN

  if (!token || token.length === 0) {
    console.log(
      '\x1b[33mNo HUBOT_SLACK_TOKEN found.\x1b[0m Please add it to your environment variables (for production) or to your .env file (for local development).\n'
    )
    process.exit()
  } else if (
    token.indexOf(tokenStart) !== 0 ||
    token.length <= tokenStart.length
  ) {
    console.warn(
      '\x1b[33mInvalid HUBOT_SLACK_TOKEN found.\x1b[0m Please check your environment variable (for production) or your .env file (for local development).\n'
    )
    process.exit()
  }
}

function convertConfigIntoParameters (config) {
  const params = []

  config.forEach((c, index) => {
    c = c.trim()

    // should the parameter be quoted?
    if (c.indexOf(' ') !== -1 && c.indexOf('="') === -1) {
      c = c.replace('=', '="') + '"'
    }

    params.push(c)

    // add cross-env
    if (index !== config.length - 1) {
      params.push('cross-env')
    }
  })

  return params
}