openURL(url: string): Promise<any> {
    Linking._validateURL(url);
    return LinkingManager.openURL(url);
  }
Try to open the given `url` with any of the installed apps.

You can use other URLs, like a location (e.g. "geo:37.484847,-122.148386" on Android
or "http://maps.apple.com/?ll=37.484847,-122.148386" on iOS), a contact,
or any other URL that can be opened with the installed apps.

The method returns a `Promise` object. If the user confirms the open dialog or the
url automatically opens, the promise is resolved.  If the user cancels the open dialog
or there are no registered applications for the url, the promise is rejected.

NOTE: This method will fail if the system doesn't know how to open the specified URL.
If you're passing in a non-http(s) URL, it's best to check {@code canOpenURL} first.

NOTE: For web URLs, the protocol ("http://", "https://") must be set accordingly!