Use cached empty AST instances in apply (#1272)

zio · Feb 1, 2025 · 95e7f2e · 95e7f2e
1 parent 3c71461
commit 95e7f2e
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Showing 2 changed files with 30 additions and 5 deletions.
diff --git a/zio-json/shared/src/main/scala/zio/json/ast/ast.scala b/zio-json/shared/src/main/scala/zio/json/ast/ast.scala
@@ -376,9 +376,15 @@ object Json {
     override def mapObjectEntries(f: ((String, Json)) => (String, Json)): Json.Obj = Json.Obj(fields.map(f))
   }
   object Obj {
-    val empty: Obj = Obj(Chunk.empty)
+    val empty: Obj = new Obj(Chunk.empty)
 
-    def apply(fields: (String, Json)*): Obj = Obj(Chunk(fields: _*))
+    def apply(chunk: Chunk[(String, Json)]): Obj =
+      if (chunk.isEmpty) empty
+      else new Obj(chunk)
+
+    def apply(fields: (String, Json)*): Obj =
+      if (fields.isEmpty) Obj.empty
+      else new Obj(Chunk(fields: _*))
 
     private lazy val objd = JsonDecoder.keyValueChunk[String, Json]
     implicit val decoder: JsonDecoder[Obj] = new JsonDecoder[Obj] {
@@ -423,9 +429,15 @@ object Json {
     override def mapArrayValues(f: Json => Json): Json.Arr         = Json.Arr(elements.map(f))
   }
   object Arr {
-    val empty: Arr = Arr(Chunk.empty)
+    val empty: Arr = new Arr(Chunk.empty)
+
+    def apply(chunk: Chunk[Json]): Arr =
+      if (chunk.isEmpty) empty
+      else new Arr(chunk)
 
-    def apply(elements: Json*): Arr = Arr(Chunk(elements: _*))
+    def apply(elements: Json*): Arr =
+      if (elements.isEmpty) empty
+      else new Arr(Chunk(elements: _*))
 
     private lazy val arrd = JsonDecoder.chunk[Json]
     implicit val decoder: JsonDecoder[Arr] = new JsonDecoder[Arr] {
@@ -595,5 +607,7 @@ object Json {
 
   implicit val codec: JsonCodec[Json] = JsonCodec(encoder, decoder)
 
-  def apply(fields: (String, Json)*): Json = Json.Obj(Chunk(fields: _*))
+  def apply(fields: (String, Json)*): Json =
+    if (fields.isEmpty) Obj.empty
+    else new Obj(Chunk(fields: _*))
 }
diff --git a/zio-json/shared/src/test/scala/zio/json/ast/JsonSpec.scala b/zio-json/shared/src/test/scala/zio/json/ast/JsonSpec.scala
@@ -9,6 +9,17 @@ object JsonSpec extends ZIOSpecDefault {
 
   val spec: Spec[Environment, Any] =
     suite("Json")(
+      suite("apply")(
+        test("()") {
+          assertTrue(Json.Obj.empty eq Json()) &&
+          assertTrue(Json.Obj.empty eq Json.Obj()) &&
+          assertTrue(Json.Arr.empty eq Json.Arr())
+        },
+        test("(Chunk.empty)") {
+          assertTrue(Json.Obj.empty eq Json.Obj(Chunk.empty)) &&
+          assertTrue(Json.Arr.empty eq Json.Arr(Chunk.empty))
+        }
+      ),
       suite("delete")(
         suite("scalar")(
           test("success") {