From 1ac3d06c90dc952b0beff9a722cfaace5162bb21 Mon Sep 17 00:00:00 2001
From: Giulio Canti <giulio.canti@gmail.com>
Date: Fri, 12 May 2023 09:38:26 +0200
Subject: [PATCH] remove undefined from optionFromNullable (#277)

---
 .changeset/healthy-points-care.md |  5 +++++
 README.md                         |  6 +++---
 docs/modules/Schema.ts.md         |  2 +-
 dtslint/ts4.9/Schema.ts           | 10 ++++++++++
 src/Schema.ts                     |  4 ++--
 test/data/Option.ts               |  8 ++++++--
 6 files changed, 27 insertions(+), 8 deletions(-)
 create mode 100644 .changeset/healthy-points-care.md

diff --git a/.changeset/healthy-points-care.md b/.changeset/healthy-points-care.md
new file mode 100644
index 000000000..f6cf45bcb
--- /dev/null
+++ b/.changeset/healthy-points-care.md
@@ -0,0 +1,5 @@
+---
+"@effect/schema": minor
+---
+
+remove undefined from optionFromNullable
diff --git a/README.md b/README.md
index 289bc969a..6e634b032 100644
--- a/README.md
+++ b/README.md
@@ -1299,7 +1299,7 @@ import * as O from "@effect/data/Option";
 /*
 const schema: S.Schema<{
     readonly a: string;
-    readonly b: number | null | undefined;
+    readonly b: number | null;
 }, {
     readonly a: string;
     readonly b: O.Option<number>;
@@ -1312,11 +1312,11 @@ const schema = S.struct({
 
 // parsing
 const parse = S.parse(schema);
-parse({ a: "hello", b: undefined }); // { a: "hello", b: none() }
 parse({ a: "hello", b: null }); // { a: "hello", b: none() }
 parse({ a: "hello", b: 1 }); // { a: "hello", b: some(1) }
 
-parse({ a: "hello" }); // throws key "b" is missing
+parse({ a: "hello", b: undefined }); // throws
+parse({ a: "hello" }); // throws (key "b" is missing)
 
 // encoding
 const encodeOrThrow = S.encode(schema);
diff --git a/docs/modules/Schema.ts.md b/docs/modules/Schema.ts.md
index d56156edc..a9414d448 100644
--- a/docs/modules/Schema.ts.md
+++ b/docs/modules/Schema.ts.md
@@ -1626,7 +1626,7 @@ Added in v1.0.0
 **Signature**
 
 ```ts
-export declare const optionFromNullable: <I, A>(value: Schema<I, A>) => Schema<I | null | undefined, Option<A>>
+export declare const optionFromNullable: <I, A>(value: Schema<I, A>) => Schema<I | null, Option<A>>
 ```
 
 Added in v1.0.0
diff --git a/dtslint/ts4.9/Schema.ts b/dtslint/ts4.9/Schema.ts
index de3fc6c1d..606132d8e 100644
--- a/dtslint/ts4.9/Schema.ts
+++ b/dtslint/ts4.9/Schema.ts
@@ -441,6 +441,16 @@ S.optionFromSelf(S.number)
 // $ExpectType Schema<Option<string>, Option<number>>
 S.optionFromSelf(NumberFromString)
 
+// ---------------------------------------------
+// optionFromNullable
+// ---------------------------------------------
+
+// $ExpectType Schema<number | null, Option<number>>
+S.optionFromNullable(S.number)
+
+// $ExpectType Schema<string | null, Option<number>>
+S.optionFromNullable(NumberFromString)
+
 // ---------------------------------------------
 // instanceOf
 // ---------------------------------------------
diff --git a/src/Schema.ts b/src/Schema.ts
index 5f88f933b..3e962d87b 100644
--- a/src/Schema.ts
+++ b/src/Schema.ts
@@ -2250,8 +2250,8 @@ export const option = <I, A>(
  */
 export const optionFromNullable = <I, A>(
   value: Schema<I, A>
-): Schema<I | null | undefined, Option<A>> =>
-  transform(union(_undefined, _null, value), to(optionFromSelf(value)), O.fromNullable, O.getOrNull)
+): Schema<I | null, Option<A>> =>
+  transform(nullable(value), to(optionFromSelf(value)), O.fromNullable, O.getOrNull)
 
 // ---------------------------------------------
 // data/ReadonlyArray
diff --git a/test/data/Option.ts b/test/data/Option.ts
index f2b0fb918..b3e3d0ac5 100644
--- a/test/data/Option.ts
+++ b/test/data/Option.ts
@@ -63,17 +63,21 @@ describe.concurrent("Option", () => {
 
     it("Decoder", async () => {
       const schema = S.optionFromNullable(NumberFromString)
-      await Util.expectParseSuccess(schema, undefined, O.none())
       await Util.expectParseSuccess(schema, null, O.none())
       await Util.expectParseSuccess(schema, "1", O.some(1))
 
       expect(O.isOption(S.decode(schema)(null))).toEqual(true)
       expect(O.isOption(S.decode(schema)("1"))).toEqual(true)
 
+      await Util.expectParseFailure(
+        schema,
+        undefined,
+        `union member: Expected null, actual undefined, union member: Expected string, actual undefined`
+      )
       await Util.expectParseFailure(
         schema,
         {},
-        `union member: Expected undefined, actual {}, union member: Expected null, actual {}, union member: Expected string, actual {}`
+        `union member: Expected null, actual {}, union member: Expected string, actual {}`
       )
     })