# Finishing the Transformation

Now that we have all of the pieces of our transformation we can refactor
our `distance` function.

The basic idea is that we want to split our the lat/lon of each
coordinate, convert those DMS coordinates to a decimal format, pass the
resulting coordinates into `haversine` and then rounding the result.

After doing this refactoring, our tests still pass!

index.js

@@ -28,5 +28,13 @@ export function haversine(lat1, lon1, lat2, lon2, R) {
 }
 
 export function distance(coord1, coord2) {
-    return 0;
+    return _.chain([coord1, coord2])
+        .map(splitOnLatLon)
+        .flatten()
+        .map(toDecimal)
+        .thru(([lat1, lon1, lat2, lon2]) => haversine(lat1, lon1, lat2, lon2, 6371))
+        .divide(10)
+        .floor()
+        .multiply(10)
+        .value();
 }