function filter(mMap, fnFilter) {
			return Object.keys(mMap).filter(fnFilter).reduce(copyTo.bind(mMap), {});
		}
function filter(mMap, fnFilter) {
			return Object.keys(mMap).filter(fnFilter).reduce(copyTo.bind(mMap), {});
		}
function filter ( mMap , fnFilter ) { return Object . keys ( mMap ) . filter ( fnFilter ) . reduce ( copyTo . bind ( mMap ) , { } ) ; }
filters the given map according to the given filter function for keys
filters the given map according to the given filter function for keys
Filter the given map by a function.