representation mapping

Mapper.ex

defmodule Mapper do
  @x_mapping [bar: [:baar], constant: [:constant], foo: [:fooo], stuffiness: [:stuff, :stuffiness], thing_other: [:thing, :other], thing_sub: [:thing, :sub]]
  
  def for_x(source_data) do
    mapper_for(@x_mapping).(source_data)
  end
  
  defp mapper_for(mapping) do
    &Enum.map(&1, fn input -> Map.new(mapping, fn {dest, src} -> {dest, get_in(input, src)} end) end)
  end
end

data = [
  %{
    constant: "just stay there",
    fooo: "foovalue",
    baar: "barvalue",
    thing: %{sub: "thing subfield", other: "thing anotherfield", discard: "nobodycares"},
    stuff: %{stuff: true, stuffiness: "extreme"}
  },
  %{
    constant: "just stay there as well",
    fooo: "foovalue2",
    baar: "barvalue2",
    thing: %{sub: "thing subfield2", other: "thing anotherfield2", discard: "nobodycares"},
    stuff: %{stuff: true, stuffiness: "moderate"}
  },
]

Mapper.for_x(data)