Use of deferreds and pipe

deferreds_pipe

fetchCurrentPosition()
	.then(updateLocationDisplay)
	.pipe(fetchWeatherAtThisLocation)
		.then(updateWeatherDisplay)
		.pipe(determineWeatherType)
			.then(updateRecommendations)
			.then(updateAppTile);

function fetchCurrentPosition()
{
	var deferred = $.Deferred();
	navigator.geolocation.getCurrentPosition(
		function( position ) {
			deferred.resolve( position );
		},
		function( error ) {
			reportError("geolocation", error);
			deferred.reject( error );
		}
	);
	return deferred.promise();
}