index.ts

export type DetectedInfoType =
  | 'browser'
  | 'node'
  | 'bot-device'
  | 'bot'
  | 'react-native';

interface DetectedInfo<
  T extends DetectedInfoType,
  N extends string,
  O,
  V = null
> {
  readonly type: T;
  readonly name: N;
  readonly version: V;
  readonly os: O;
}

export class BrowserInfo
  implements DetectedInfo<'browser', Browser, OperatingSystem | null, string> {
  public readonly type = 'browser';
  constructor(
    public readonly name: Browser,
    public readonly version: string,
    public readonly os: OperatingSystem | null,
  ) {}
}

export class NodeInfo
  implements DetectedInfo<'node', 'node', NodeJS.Platform, string> {
  public readonly type = 'node';
  public readonly name: 'node' = 'node';
  public readonly os: NodeJS.Platform = process.platform;

  constructor(public readonly version: string) {}
}

export class SearchBotDeviceInfo
  implements
    DetectedInfo<'bot-device', Browser, OperatingSystem | null, string> {
  public readonly type = 'bot-device';
  constructor(
    public readonly name: Browser,
    public readonly version: string,
    public readonly os: OperatingSystem | null,
    public readonly bot: string,
  ) {}
}

export class BotInfo implements DetectedInfo<'bot', 'bot', null, null> {
  public readonly type = 'bot';
  public readonly bot: true = true; // NOTE: deprecated test name instead
  public readonly name: 'bot' = 'bot';
  public readonly version: null = null;
  public readonly os: null = null;
}

export class ReactNativeInfo
  implements DetectedInfo<'react-native', 'react-native', null, null> {
  public readonly type = 'react-native';
  public readonly name: 'react-native' = 'react-native';
  public readonly version: null = null;
  public readonly os: null = null;
}

export type Browser =
  | 'aol'
  | 'edge'
  | 'edge-ios'
  | 'yandexbrowser'
  | 'kakaotalk'
  | 'samsung'
  | 'silk'
  | 'miui'
  | 'beaker'
  | 'edge-chromium'
  | 'chrome'
  | 'chromium-webview'
  | 'phantomjs'
  | 'crios'
  | 'firefox'
  | 'fxios'
  | 'opera-mini'
  | 'opera'
  | 'ie'
  | 'bb10'
  | 'android'
  | 'ios'
  | 'safari'
  | 'facebook'
  | 'instagram'
  | 'ios-webview'
  | 'curl'
  | 'searchbot';
export type OperatingSystem =
  | 'iOS'
  | 'Android OS'
  | 'BlackBerry OS'
  | 'Windows Mobile'
  | 'Amazon OS'
  | 'Windows 3.11'
  | 'Windows 95'
  | 'Windows 98'
  | 'Windows 2000'
  | 'Windows XP'
  | 'Windows Server 2003'
  | 'Windows Vista'
  | 'Windows 7'
  | 'Windows 8'
  | 'Windows 8.1'
  | 'Windows 10'
  | 'Windows ME'
  | 'Open BSD'
  | 'Sun OS'
  | 'Linux'
  | 'Mac OS'
  | 'QNX'
  | 'BeOS'
  | 'OS/2'
  | 'Chrome OS';
type UserAgentRule = [Browser, RegExp];
type UserAgentMatch = [Browser, RegExpExecArray] | false;
type OperatingSystemRule = [OperatingSystem, RegExp];

// tslint:disable-next-line:max-line-length
const SEARCHBOX_UA_REGEX = /alexa|bot|crawl(er|ing)|facebookexternalhit|feedburner|google web preview|nagios|postrank|pingdom|slurp|spider|yahoo!|yandex/;
const SEARCHBOT_OS_REGEX = /(nuhk|curl|Googlebot|Yammybot|Openbot|Slurp|MSNBot|Ask\ Jeeves\/Teoma|ia_archiver)/;
const REQUIRED_VERSION_PARTS = 3;

const userAgentRules: UserAgentRule[] = [
  ['aol', /AOLShield\/([0-9\._]+)/],
  ['edge', /Edge\/([0-9\._]+)/],
  ['edge-ios', /EdgiOS\/([0-9\._]+)/],
  ['yandexbrowser', /YaBrowser\/([0-9\._]+)/],
  ['kakaotalk', /KAKAOTALK\s([0-9\.]+)/],
  ['samsung', /SamsungBrowser\/([0-9\.]+)/],
  ['silk', /\bSilk\/([0-9._-]+)\b/],
  ['miui', /MiuiBrowser\/([0-9\.]+)$/],
  ['beaker', /BeakerBrowser\/([0-9\.]+)/],
  ['edge-chromium', /EdgA?\/([0-9\.]+)/],
  [
    'chromium-webview',
    /(?!Chrom.*OPR)wv\).*Chrom(?:e|ium)\/([0-9\.]+)(:?\s|$)/,
  ],
  ['chrome', /(?!Chrom.*OPR)Chrom(?:e|ium)\/([0-9\.]+)(:?\s|$)/],
  ['phantomjs', /PhantomJS\/([0-9\.]+)(:?\s|$)/],
  ['crios', /CriOS\/([0-9\.]+)(:?\s|$)/],
  ['firefox', /Firefox\/([0-9\.]+)(?:\s|$)/],
  ['fxios', /FxiOS\/([0-9\.]+)/],
  ['opera-mini', /Opera Mini.*Version\/([0-9\.]+)/],
  ['opera', /Opera\/([0-9\.]+)(?:\s|$)/],
  ['opera', /OPR\/([0-9\.]+)(:?\s|$)/],
  ['ie', /Trident\/7\.0.*rv\:([0-9\.]+).*\).*Gecko$/],
  ['ie', /MSIE\s([0-9\.]+);.*Trident\/[4-7].0/],
  ['ie', /MSIE\s(7\.0)/],
  ['bb10', /BB10;\sTouch.*Version\/([0-9\.]+)/],
  ['android', /Android\s([0-9\.]+)/],
  ['ios', /Version\/([0-9\._]+).*Mobile.*Safari.*/],
  ['safari', /Version\/([0-9\._]+).*Safari/],
  ['facebook', /FB[AS]V\/([0-9\.]+)/],
  ['instagram', /Instagram\s([0-9\.]+)/],
  ['ios-webview', /AppleWebKit\/([0-9\.]+).*Mobile/],
  ['ios-webview', /AppleWebKit\/([0-9\.]+).*Gecko\)$/],
  ['curl', /^curl\/([0-9\.]+)$/],
  ['searchbot', SEARCHBOX_UA_REGEX],
];
const operatingSystemRules: OperatingSystemRule[] = [
  ['iOS', /iP(hone|od|ad)/],
  ['Android OS', /Android/],
  ['BlackBerry OS', /BlackBerry|BB10/],
  ['Windows Mobile', /IEMobile/],
  ['Amazon OS', /Kindle/],
  ['Windows 3.11', /Win16/],
  ['Windows 95', /(Windows 95)|(Win95)|(Windows_95)/],
  ['Windows 98', /(Windows 98)|(Win98)/],
  ['Windows 2000', /(Windows NT 5.0)|(Windows 2000)/],
  ['Windows XP', /(Windows NT 5.1)|(Windows XP)/],
  ['Windows Server 2003', /(Windows NT 5.2)/],
  ['Windows Vista', /(Windows NT 6.0)/],
  ['Windows 7', /(Windows NT 6.1)/],
  ['Windows 8', /(Windows NT 6.2)/],
  ['Windows 8.1', /(Windows NT 6.3)/],
  ['Windows 10', /(Windows NT 10.0)/],
  ['Windows ME', /Windows ME/],
  ['Open BSD', /OpenBSD/],
  ['Sun OS', /SunOS/],
  ['Chrome OS', /CrOS/],
  ['Linux', /(Linux)|(X11)/],
  ['Mac OS', /(Mac_PowerPC)|(Macintosh)/],
  ['QNX', /QNX/],
  ['BeOS', /BeOS/],
  ['OS/2', /OS\/2/],
];

export function detect(
  userAgent?: string,
):
  | BrowserInfo
  | SearchBotDeviceInfo
  | BotInfo
  | NodeInfo
  | ReactNativeInfo
  | null {
  if (!!userAgent) {
    return parseUserAgent(userAgent);
  }

  if (
    typeof document === 'undefined' &&
    typeof navigator !== 'undefined' &&
    navigator.product === 'ReactNative'
  ) {
    return new ReactNativeInfo();
  }

  if (typeof navigator !== 'undefined') {
    return parseUserAgent(navigator.userAgent);
  }

  return getNodeVersion();
}

function matchUserAgent(ua: string): UserAgentMatch {
  // opted for using reduce here rather than Array#first with a regex.test call
  // this is primarily because using the reduce we only perform the regex
  // execution once rather than once for the test and for the exec again below
  // probably something that needs to be benchmarked though
  return (
    ua !== '' &&
    userAgentRules.reduce<UserAgentMatch>(
      (matched: UserAgentMatch, [browser, regex]) => {
        if (matched) {
          return matched;
        }

        const uaMatch = regex.exec(ua);
        return !!uaMatch && [browser, uaMatch];
      },
      false,
    )
  );
}

export function browserName(ua: string): Browser | null {
  const data = matchUserAgent(ua);
  return data ? data[0] : null;
}

export function parseUserAgent(
  ua: string,
): BrowserInfo | SearchBotDeviceInfo | BotInfo | null {
  const matchedRule: UserAgentMatch = matchUserAgent(ua);

  if (!matchedRule) {
    return null;
  }

  const [name, match] = matchedRule;
  if (name === 'searchbot') {
    return new BotInfo();
  }
  // Do not use RegExp for split operation as some browser do not support it (See: http://blog.stevenlevithan.com/archives/cross-browser-split)
  let versionParts = match[1] && match[1].split('.').join('_').split('_').slice(0, 3);
  if (versionParts) {
    if (versionParts.length < REQUIRED_VERSION_PARTS) {
      versionParts = [
        ...versionParts,
        ...createVersionParts(REQUIRED_VERSION_PARTS - versionParts.length),
      ];
    }
  } else {
    versionParts = [];
  }

  const version = versionParts.join('.');
  const os = detectOS(ua);
  const searchBotMatch = SEARCHBOT_OS_REGEX.exec(ua);

  if (searchBotMatch && searchBotMatch[1]) {
    return new SearchBotDeviceInfo(name, version, os, searchBotMatch[1]);
  }

  return new BrowserInfo(name, version, os);
}

export function detectOS(ua: string): OperatingSystem | null {
  for (let ii = 0, count = operatingSystemRules.length; ii < count; ii++) {
    const [os, regex] = operatingSystemRules[ii];
    const match = regex.exec(ua);
    if (match) {
      return os;
    }
  }

  return null;
}

export function getNodeVersion(): NodeInfo | null {
  const isNode = typeof process !== 'undefined' && process.version;
  return isNode ? new NodeInfo(process.version.slice(1)) : null;
}

function createVersionParts(count: number): string[] {
  const output = [];
  for (let ii = 0; ii < count; ii++) {
    output.push('0');
  }

  return output;
}