Having long object literals containing the code is problematic.
It makes it difficult to add auxiliary functions or data close to the
function inside the map where it is needed.
Building the map in several steps, repeating the map name at each step,
avoids that problem since it makes the definitions independent from one
another, so anything can go between them.
This commit deliberately avoided reindenting existing code to match the new
surroundings. That way it is easier to see where actual changes happen,
even when not performing a whitespace-ignoring diff.
6bc7cd574f