I have a list of maps that provide a type of property lookup, and a map with values.

lookup =
  [
    %{key: "foo", type: :string},
    %{key: "bar", type: :string},
    %{key: "baz", type: :string}
  ]

params = %{foo: "bananas", baz: "apples}

What I’ve been attempting to do (unsuccessfully) is to use Enum.reduce, for lack of a better approach, in order to combine the two into the following format, while discarding any lookup keys that aren’t present in values:

output =
  [
    %{key: :foo, value: "bananas", type: :string},
    %{key: :baz, value: "apples", type: :string},
  ]

I had tried this, but I can’t work out how to access the value from params using the atom key from lookup.

def clever_merge(lookup, params) do
  Enum.reduce(lookup, [], fn(%{key: k, type: t}, output) ->
    with rec <- %{key: String.to_atom(k), value: params.k, type: t} do
      List.insert_at(output, -1, rec)
    end
  end)
end

The other issue is filtering out keys that aren’t present in params. I tried a few combinations of if statements around Enum.reduce but I couldn’t work it out.

I know it’s always a big ask but could someone point me in the right direction please?

Thanks.