Reduce orientation events coming from react-native-orientation npm module

reduceOrientation.js

function _reduceOrientation(lastOrientation, orientation) {

	if(orientation==='UNKNOWN' && lastOrientation==='UNKNOWN') {
		return 'UNKNOWN';
	}
		
	switch(orientation) {
			case 'LANDSCAPE':
			case 'PORTRAIT':
				return orientation;
			case 'UNKNOWN':
			  return lastOrientation;
	}
		
}

Expected output:

console.log(_reduceOrientation('UNKNOWN', 'UNKNOWN')); // UNKNOWN
console.log(_reduceOrientation('PORTRAIT', 'UNKNOWN')); // PORTRAIT 
console.log(_reduceOrientation('LANDSCAPE', 'UNKNOWN')); // LANDSCAPE

console.log(_reduceOrientation('UNKNOWN', 'PORTRAIT')); // PORTRAIT
console.log(_reduceOrientation('LANDSCAPE', 'PORTRAIT')); // PORTRAIT
console.log(_reduceOrientation('PORTRAIT', 'PORTRAIT')); // PORTRAIT

console.log(_reduceOrientation('UNKNOWN', 'LANDSCAPE')); // LANDSCAPE
console.log(_reduceOrientation('PORTRAIT', 'LANDSCAPE')); // LANDSCAPE
console.log(_reduceOrientation('LANDSCAPE', 'LANDSCAPE')); // LANDSCAPE