From 7066a54e17dcf2f09b8201b5739860961fc58f70 Mon Sep 17 00:00:00 2001
From: Thijs Broersen <4889512+ThijsBroersen@users.noreply.github.com>
Date: Sun, 20 Oct 2024 19:11:59 +0200
Subject: [PATCH] feat: support ListMap (#1177)

---
 zio-json/shared/src/main/scala/zio/json/JsonCodec.scala   | 4 ++++
 zio-json/shared/src/main/scala/zio/json/JsonDecoder.scala | 7 +++++++
 zio-json/shared/src/main/scala/zio/json/JsonEncoder.scala | 3 +++
 zio-json/shared/src/test/scala/zio/json/CodecSpec.scala   | 6 ++++++
 zio-json/shared/src/test/scala/zio/json/DecoderSpec.scala | 6 ++++++
 zio-json/shared/src/test/scala/zio/json/EncoderSpec.scala | 3 +++
 6 files changed, 29 insertions(+)

diff --git a/zio-json/shared/src/main/scala/zio/json/JsonCodec.scala b/zio-json/shared/src/main/scala/zio/json/JsonCodec.scala
index 7034775b..32e3c53e 100644
--- a/zio-json/shared/src/main/scala/zio/json/JsonCodec.scala
+++ b/zio-json/shared/src/main/scala/zio/json/JsonCodec.scala
@@ -157,6 +157,10 @@ private[json] trait CodecLowPriority1 extends CodecLowPriority2 { this: JsonCode
 
   implicit def sortedSet[A: Ordering: JsonEncoder: JsonDecoder]: JsonCodec[immutable.SortedSet[A]] =
     JsonCodec(JsonEncoder.sortedSet[A], JsonDecoder.sortedSet[A])
+
+  implicit def listMap[K: JsonFieldEncoder: JsonFieldDecoder, V: JsonEncoder: JsonDecoder]
+    : JsonCodec[immutable.ListMap[K, V]] =
+    JsonCodec(JsonEncoder.listMap[K, V], JsonDecoder.listMap[K, V])
 }
 
 private[json] trait CodecLowPriority2 extends CodecLowPriority3 { this: JsonCodec.type =>
diff --git a/zio-json/shared/src/main/scala/zio/json/JsonDecoder.scala b/zio-json/shared/src/main/scala/zio/json/JsonDecoder.scala
index ddf45c72..5be8a54e 100644
--- a/zio-json/shared/src/main/scala/zio/json/JsonDecoder.scala
+++ b/zio-json/shared/src/main/scala/zio/json/JsonDecoder.scala
@@ -597,6 +597,13 @@ private[json] trait DecoderLowPriority1 extends DecoderLowPriority2 {
       def unsafeDecode(trace: List[JsonError], in: RetractReader): collection.SortedMap[K, V] =
         keyValueBuilder(trace, in, collection.SortedMap.newBuilder[K, V])
     }
+
+  implicit def listMap[K: JsonFieldDecoder, V: JsonDecoder]: JsonDecoder[immutable.ListMap[K, V]] =
+    new JsonDecoder[immutable.ListMap[K, V]] {
+
+      def unsafeDecode(trace: List[JsonError], in: RetractReader): immutable.ListMap[K, V] =
+        keyValueBuilder(trace, in, immutable.ListMap.newBuilder[K, V])
+    }
 }
 
 // We have a hierarchy of implicits for two reasons:
diff --git a/zio-json/shared/src/main/scala/zio/json/JsonEncoder.scala b/zio-json/shared/src/main/scala/zio/json/JsonEncoder.scala
index 6b1dc40e..7098a1b8 100644
--- a/zio-json/shared/src/main/scala/zio/json/JsonEncoder.scala
+++ b/zio-json/shared/src/main/scala/zio/json/JsonEncoder.scala
@@ -377,6 +377,9 @@ private[json] trait EncoderLowPriority1 extends EncoderLowPriority2 {
 
   implicit def sortedMap[K: JsonFieldEncoder, V: JsonEncoder]: JsonEncoder[collection.SortedMap[K, V]] =
     keyValueIterable[K, V, collection.SortedMap]
+
+  implicit def listMap[K: JsonFieldEncoder, V: JsonEncoder]: JsonEncoder[immutable.ListMap[K, V]] =
+    keyValueIterable[K, V, immutable.ListMap]
 }
 
 private[json] trait EncoderLowPriority2 extends EncoderLowPriority3 {
diff --git a/zio-json/shared/src/test/scala/zio/json/CodecSpec.scala b/zio-json/shared/src/test/scala/zio/json/CodecSpec.scala
index 57f70b13..1cd755c7 100644
--- a/zio-json/shared/src/test/scala/zio/json/CodecSpec.scala
+++ b/zio-json/shared/src/test/scala/zio/json/CodecSpec.scala
@@ -182,6 +182,12 @@ object CodecSpec extends ZIOSpecDefault {
 
           assert(jsonStr.fromJson[Map[String, Int]])(isRight(equalTo(expected)))
         },
+        test("ListMap") {
+          val jsonStr  = """{"5XL":3,"2XL":14,"XL":159}"""
+          val expected = collection.immutable.ListMap("5XL" -> 3, "2XL" -> 14, "XL" -> 159)
+
+          assert(jsonStr.fromJson[collection.immutable.ListMap[String, Int]])(isRight(equalTo(expected)))
+        },
         test("zio.Chunk") {
           val jsonStr  = """["5XL","2XL","XL"]"""
           val expected = Chunk("5XL", "2XL", "XL")
diff --git a/zio-json/shared/src/test/scala/zio/json/DecoderSpec.scala b/zio-json/shared/src/test/scala/zio/json/DecoderSpec.scala
index 73353af8..7f65c752 100644
--- a/zio-json/shared/src/test/scala/zio/json/DecoderSpec.scala
+++ b/zio-json/shared/src/test/scala/zio/json/DecoderSpec.scala
@@ -494,6 +494,12 @@ object DecoderSpec extends ZIOSpecDefault {
 
           assert(json.as[SortedMap[String, Int]])(isRight(equalTo(expected)))
         },
+        test("ListMap") {
+          val json     = Json.Obj("5XL" -> Json.Num(3), "2XL" -> Json.Num(14), "XL" -> Json.Num(159))
+          val expected = immutable.ListMap("5XL" -> 3, "2XL" -> 14, "XL" -> 159)
+
+          assert(json.as[immutable.ListMap[String, Int]])(isRight(equalTo(expected)))
+        },
         test("Map, custom keys") {
           val json     = Json.Obj("1" -> Json.Str("a"), "2" -> Json.Str("b"))
           val expected = Map(1 -> "a", 2 -> "b")
diff --git a/zio-json/shared/src/test/scala/zio/json/EncoderSpec.scala b/zio-json/shared/src/test/scala/zio/json/EncoderSpec.scala
index 59f484d4..914099e6 100644
--- a/zio-json/shared/src/test/scala/zio/json/EncoderSpec.scala
+++ b/zio-json/shared/src/test/scala/zio/json/EncoderSpec.scala
@@ -256,6 +256,9 @@ object EncoderSpec extends ZIOSpecDefault {
           assert(Map("hello" -> "world").toJsonPretty)(equalTo("{\n  \"hello\" : \"world\"\n}")) &&
           assert(Map("hello" -> Some("world"), "goodbye" -> None).toJsonPretty)(
             equalTo("{\n  \"hello\" : \"world\"\n}")
+          ) &&
+          assert(immutable.ListMap("hello" -> "world", "goodbye" -> "world").toJson)(
+            equalTo("""{"hello":"world","goodbye":"world"}""")
           )
         },
         test("Map, custom keys") {