From 8e502b43f64c62ea605cd521524835a44890a5c8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jos=C3=A9=20Valim?= <jose.valim@dashbit.co>
Date: Wed, 11 Dec 2024 18:09:10 +0100
Subject: [PATCH] Implement JSON.Encoder for Calendar types

---
 lib/elixir/lib/json.ex               | 6 ++++++
 lib/elixir/test/elixir/json_test.exs | 7 +++++++
 2 files changed, 13 insertions(+)

diff --git a/lib/elixir/lib/json.ex b/lib/elixir/lib/json.ex
index 36a2be3d8a8..c41f700f171 100644
--- a/lib/elixir/lib/json.ex
+++ b/lib/elixir/lib/json.ex
@@ -150,6 +150,12 @@ defimpl JSON.Encoder, for: Map do
   end
 end
 
+defimpl JSON.Encoder, for: [Date, Time, NaiveDateTime, DateTime] do
+  def encode(value, _encoder) do
+    [?", @for.to_iso8601(value), ?"]
+  end
+end
+
 defmodule JSON.DecodeError do
   @moduledoc """
   The exception raised by `JSON.decode!/1`.
diff --git a/lib/elixir/test/elixir/json_test.exs b/lib/elixir/test/elixir/json_test.exs
index 8e301944834..99b8d23cd6d 100644
--- a/lib/elixir/test/elixir/json_test.exs
+++ b/lib/elixir/test/elixir/json_test.exs
@@ -46,6 +46,13 @@ defmodule JSONTest do
       assert JSON.encode!(%Token{value: :example}) == "[\"example\"]"
       assert JSON.encode!(%Token{value: "hello\0world"}) == "[\"hello\\u0000world\"]"
     end
+
+    test "calendar" do
+      assert JSON.encode!(~D[2010-04-17]) == "\"2010-04-17\""
+      assert JSON.encode!(~T[14:00:00.123]) == "\"14:00:00.123\""
+      assert JSON.encode!(~N[2010-04-17 14:00:00.123]) == "\"2010-04-17T14:00:00.123\""
+      assert JSON.encode!(~U[2010-04-17 14:00:00.123Z]) == "\"2010-04-17T14:00:00.123Z\""
+    end
   end
 
   describe "JSON.Encoder" do