/**
 * (Private, not exported from the package) Reads the kind of device a User-Agent string
 * names, for `isMobileDeviceFromUa`, `isTabletDeviceFromUa` and `isDesktopDeviceFromUa`.
 *
 * The checks run in order and the first one that answers wins, so the three functions can
 * never all agree on one string: a tablet is tested before a phone because an iPad's Safari
 * also says `Mobile`, and an Android string that names no phone is a tablet only after
 * every phone pattern has had its turn. A string that names no device at all, such as
 * `curl/8.0` or most crawlers, is none of the three.
 */
export type DeviceType = 'mobile' | 'tablet' | 'desktop';
export declare function deviceType(userAgent: string): DeviceType | null;