node_modules/color-support/index.js

// call it on itself so we can test the export val for basic stuff
module.exports = colorSupport({ alwaysReturn: true }, colorSupport)

function hasNone (obj, options) {
  obj.level = 0
  obj.hasBasic = false
  obj.has256 = false
  obj.has16m = false
  if (!options.alwaysReturn) {
    return false
  }
  return obj
}

function hasBasic (obj) {
  obj.hasBasic = true
  obj.has256 = false
  obj.has16m = false
  obj.level = 1
  return obj
}

function has256 (obj) {
  obj.hasBasic = true
  obj.has256 = true
  obj.has16m = false
  obj.level = 2
  return obj
}

function has16m (obj) {
  obj.hasBasic = true
  obj.has256 = true
  obj.has16m = true
  obj.level = 3
  return obj
}

function colorSupport (options, obj) {
  options = options || {}

  obj = obj || {}

  // if just requesting a specific level, then return that.
  if (typeof options.level === 'number') {
    switch (options.level) {
      case 0:
        return hasNone(obj, options)
      case 1:
        return hasBasic(obj)
      case 2:
        return has256(obj)
      case 3:
        return has16m(obj)
    }
  }

  obj.level = 0
  obj.hasBasic = false
  obj.has256 = false
  obj.has16m = false

  if (typeof process === 'undefined' ||
      !process ||
      !process.stdout ||
      !process.env ||
      !process.platform) {
    return hasNone(obj, options)
  }

  var env = options.env || process.env
  var stream = options.stream || process.stdout
  var term = options.term || env.TERM || ''
  var platform = options.platform || process.platform

  if (!options.ignoreTTY && !stream.isTTY) {
    return hasNone(obj, options)
  }

  if (!options.ignoreDumb && term === 'dumb' && !env.COLORTERM) {
    return hasNone(obj, options)
  }

  if (platform === 'win32') {
    return hasBasic(obj)
  }

  if (env.TMUX) {
    return has256(obj)
  }

  if (!options.ignoreCI && (env.CI || env.TEAMCITY_VERSION)) {
    if (env.TRAVIS) {
      return has256(obj)
    } else {
      return hasNone(obj, options)
    }
  }

  // TODO: add more term programs
  switch (env.TERM_PROGRAM) {
    case 'iTerm.app':
      var ver = env.TERM_PROGRAM_VERSION || '0.'
      if (/^[0-2]\./.test(ver)) {
        return has256(obj)
      } else {
        return has16m(obj)
      }

    case 'HyperTerm':
    case 'Hyper':
      return has16m(obj)

    case 'MacTerm':
      return has16m(obj)

    case 'Apple_Terminal':
      return has256(obj)
  }

  if (/^xterm-256/.test(term)) {
    return has256(obj)
  }

  if (/^screen|^xterm|^vt100|color|ansi|cygwin|linux/i.test(term)) {
    return hasBasic(obj)
  }

  if (env.COLORTERM) {
    return hasBasic(obj)
  }

  return hasNone(obj, options)
}