Created
October 12, 2021 20:09
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| defmodule MyApp.Encoder do | |
| @moduledoc """ | |
| General implementation for the Jason encoder to be used in Ecto schemas | |
| """ | |
| defmacro __using__(opts) do | |
| drop_fields = Keyword.get(opts, :drop, []) | |
| quote do | |
| defimpl Jason.Encoder, for: [__MODULE__] do | |
| defp cardinality_to_empty(:one), do: %{} | |
| defp cardinality_to_empty(:many), do: [] | |
| def encode(struct, opts) do | |
| struct | |
| |> Map.from_struct() | |
| |> Enum.reduce(%{}, fn | |
| {k, %Ecto.Association.NotLoaded{} = v}, acc -> | |
| Map.put(acc, k, cardinality_to_empty(v.__cardinality__)) | |
| {k, v}, acc -> | |
| Map.put(acc, k, v) | |
| end) | |
| |> Map.drop([:__meta__, :__struct__] ++ unquote(drop_fields)) | |
| |> Jason.Encode.map(opts) | |
| end | |
| end | |
| end | |
| end | |
| end |
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