[viraptor]

I'd go with this since it's not performance critical code. Not sure if it's that more readable, but I like it better:

    BY_NODE_NAMES = HANDLERS.map {|h|
      h::NODE_NAMES.map {|n| [n, h]}
    }.flatten(1).to_h

[ngcazz]

I think we can go harder on the std lib :)

  HANDLERS.flat_map { _1.node_names.index_with(_1) }.inject(&:merge)

(nb: assuming there exists a `.node_names` to expose the constant... just because I like always using method calls)