function getOrientationValue (platformConfig) {
    const ORIENTATION_DEFAULT = 'default';

    let orientation = platformConfig.getPreference('orientation');
    if (!orientation) {
        return ORIENTATION_DEFAULT;
    }

    orientation = orientation.toLowerCase();

    // Check if the given global orientation is supported
    if (['default', 'portrait', 'landscape', 'all'].indexOf(orientation) >= 0) {
        return orientation;
    }

    events.emit('warn', `Unrecognized value for Orientation preference: ${orientation}. Defaulting to value: ${ORIENTATION_DEFAULT}.`);

    return ORIENTATION_DEFAULT;
}
Queries ConfigParser object for the orientation <preference> value. Warns if
  global preference value is not supported by platform.

@param  {Object} platformConfig    ConfigParser object

@return {String}           Global/platform-specific orientation in lower-case
  (or empty string if both are undefined).