mix format + more docs #2

README.md

@@ -79,9 +79,12 @@ iex> Useful.flatten_map(map)
 ```
 
 **Note**: `flatten_map/1` converts all Map keys to `Atom`
-as it's easier to work with atoms as keys e.g: `person.name` instead of `person["name"]`.
-We use the `__` (_double underscore_) as the delimiter for the keys of nested maps,
-because if we attempt to use `.` (_period character_) we get an error:
+as it's easier to work with atoms as keys
+e.g: `map.person__name` instead of `map["person__name"]`.
+We use the `__` (_double underscore_)
+as the delimiter for the keys of nested maps,
+because if we attempt to use `.` (_period character_)
+we get an error:
 
 ```elixir
 iex(1)> :a.b

lib/useful.ex

@@ -49,26 +49,30 @@ defmodule Useful do
     |> Enum.into(%{})
   end
 
+  # Recap: https://elixir-lang.org/getting-started/basic-types.html#tuples
   defp to_list_of_tuples(map) do
     map
     |> Enum.map(&process/1)
     |> List.flatten()
   end
 
-  # avoids ** (Protocol.UndefinedError) protocol Enumerable
-  # not implemented for ~U[2016-05-24 13:26:08.003Z] of type DateTime
-  defp process({key, %Date{} = date}), do: return({key, date})
-  defp process({key, %DateTime{} = datetime}), do: return({key, datetime})
+  # avoids the error "** (Protocol.UndefinedError) protocol Enumerable
+  #   not implemented for ~U[2017-08-05 16:34:08.003Z] of type DateTime"
+  defp process({key, %Date{} = date}), do: format({key, date})
+  defp process({key, %DateTime{} = datetime}), do: format({key, datetime})
 
+  # process nested maps
   defp process({key, sub_map}) when is_map(sub_map) do
     for {sub_key, value} <- flatten_map(sub_map) do
-      {String.to_atom("#{key}__#{sub_key}"), value}
+      format({"#{key}__#{sub_key}", value})
     end
   end
 
-  defp process({key, value}), do: return({key, value})
-  # defp process(value), do: value
-  defp return({key, value}) do
+  # catch-all for any type of key/value
+  defp process({key, value}), do: format({key, value})
+
+  # format the {key: value} with Atom key for simpler access
+  defp format({key, value}) do
     {String.to_atom("#{key}"), value}
   end
 end

test/useful_test.exs

@@ -9,7 +9,7 @@ defmodule UsefulTest do
   end
 
   test "atomize_map_keys/1 converts deeply nested map" do
-    map = %{"name" => "alex", id: 1, nested: %{ "age" => 17, height: 185}}
+    map = %{"name" => "alex", id: 1, nested: %{"age" => 17, height: 185}}
     # IO.inspect(map, label: "map")
     expected = Useful.atomize_map_keys(map)
     assert expected == %{id: 1, name: "alex", nested: %{age: 17, height: 185}}
@@ -23,17 +23,20 @@ defmodule UsefulTest do
 
   test "flatten_map/1 handles Date and DateTime values" do
     map = %{
-      date: Date.from_erl!({2000, 1, 1}),
+      date: Date.from_erl!({1999, 2, 14}),
       data: %{
-        dateTime: DateTime.from_naive!(~N[2016-05-24 13:26:08.003], "Etc/UTC"),
-        height: 185}
+        dateTime: DateTime.from_naive!(~N[2017-08-05 16:34:08.003], "Etc/UTC"),
+        height: 185
       }
+    }
+
     expected = Useful.flatten_map(map)
+
     assert expected == %{
-      data__dateTime: ~U[2016-05-24 13:26:08.003Z],
-      data__height: 185,
-      date: ~D[2000-01-01]
-    }
+             data__dateTime: ~U[2017-08-05 16:34:08.003Z],
+             data__height: 185,
+             date: ~D[1999-02-14]
+           }
   end
 
   test "flatten super nested map" do
@@ -52,13 +55,15 @@ defmodule UsefulTest do
         }
       }
     }
+
     expected = Useful.flatten_map(map)
+
     assert expected == %{
-      data__address__detail__house_color: "white",
-      data__address__detail__more_info__architect: "James Hoban",
-      data__address__first_line: "1600 Pennsylvania Avenue",
-      data__address__post_code: "20500",
-      name: "Alex"
-    }
+             data__address__detail__house_color: "white",
+             data__address__detail__more_info__architect: "James Hoban",
+             data__address__first_line: "1600 Pennsylvania Avenue",
+             data__address__post_code: "20500",
+             name: "Alex"
+           }
   end
-end
+end