Sunny Mapper Example

map.rb

require 'rom-mapper'
require 'pp'

data = [
  {
    departure_lat: 12,
    departure_lon: 75,
    destination_lat: 15,
    destination_lon: 80
  }
]

class MyMapper < ROM::Mapper
  step do
    attribute(:departure, from: [:departure_lat, :departure_lon]) { |lat,lon| {lat: lat, lon: lon} }
    attribute(:destination, from: [:destination_lat, :destination_lon]) { |lat,lon| {lat: lat, lon: lon} }                                                                            
  end

  step do
    attribute(:locations, from: [:departure, :destination]) { |v1, v2| [v1, v2] }
  end
end

pp MyMapper.build.call(data)