mobile-os.model.ts

enum MobileOS {
  Android = 'android',
  iOS = 'ios',
  Unknown = 'unknown',
  WindowsPhone = 'Windows Phone'
}

/**
 * https://stackoverflow.com/a/21742107
 * Determine the mobile operating system.
 *
 * @returns {MobileOS}
 */
const getMobileOS = (): MobileOS | undefined => {
  if (isMobileDevice()) {
    // Windows Phone must come first because its UA also contains "Android"
    if (/windows phone/i.test(userAgent)) return MobileOS.WindowsPhone
    else if (/android/i.test(userAgent)) return MobileOS.Android

    // iOS detection from: http://stackoverflow.com/a/9039885/177710
    if (/iPad|iPhone|iPod/.test(userAgent) && !window.MSStream) return MobileOS.iOS

    return MobileOS.Unknown
  } else return undefined
}