fix for encoding of Transferable schemas (#2027)

.changeset/ten-pandas-brake.md

@@ -0,0 +1,5 @@
+---
+"@effect/platform": minor
+---
+
+fix for encoding of Transferable schemas

packages/platform/src/Transferable.ts

@@ -37,57 +37,71 @@ export const get = (u: unknown): ReadonlyArray<globalThis.Transferable> => {
   return []
 }
 
+/**
+ * @since 1.0.0
+ * @category schema
+ */
+export interface TransferableSchema<A extends object, I, R> extends Schema.Schema<A & Transferable, I, R> {
+  (_: A): A & Transferable
+}
+
 /**
  * @since 1.0.0
  * @category schema
  */
 export const schema: {
   <A extends object>(
     f: (_: A) => ReadonlyArray<globalThis.Transferable>
-  ): <R, I>(self: Schema.Schema<A, I, R>) => Schema.Schema<A, I, R>
+  ): <R, I>(self: Schema.Schema<A, I, R>) => TransferableSchema<A, I, R>
   <R, I, A extends object>(
     self: Schema.Schema<A, I, R>,
     f: (_: A) => ReadonlyArray<globalThis.Transferable>
-  ): Schema.Schema<A, I, R>
+  ): TransferableSchema<A, I, R>
 } = dual(2, <R, I, A extends object>(
   self: Schema.Schema<A, I, R>,
   f: (_: A) => ReadonlyArray<globalThis.Transferable>
 ) => {
   const fn: Transferable[typeof symbol] = function(this: A) {
     return f(this)
   }
-  return Schema.transform(
+  const schema = Schema.transform(
     self,
     schemaFromSelf(Schema.to(self)),
     (input) => addProxy(input, fn),
     identity
   )
+  function make(self: A): A & Transferable {
+    return addProxy(self, fn)
+  }
+  Object.setPrototypeOf(make, Object.getPrototypeOf(schema))
+  make.ast = schema.ast
+  return make
 })
 
-const schemaParse =
-  <R, A extends object>(parse: ParseResult.DecodeUnknown<R, A>): ParseResult.DeclarationDecodeUnknown<R, A> =>
-  (u, options, ast) => {
-    if (!isTransferable(u)) {
-      return ParseResult.fail(ParseResult.type(ast, u))
-    }
-    const f = u[symbol]
-    return ParseResult.map(parse(u, options), (a): A => addProxy(a, f))
+const schemaParse = <R, A extends object>(
+  parse: ParseResult.DecodeUnknown<R, A>
+): ParseResult.DeclarationDecodeUnknown<R, A & Transferable> =>
+(u, options, ast) => {
+  if (!isTransferable(u)) {
+    return ParseResult.fail(ParseResult.type(ast, u))
   }
+  const f = u[symbol]
+  return ParseResult.map(parse(u, options), (a) => addProxy(a, f))
+}
 
 /**
  * @since 1.0.0
  * @category schema
  */
-export const schemaFromSelf = <R, I extends object, A extends object>(
+export const schemaFromSelf = <A extends object, I extends object, R>(
   item: Schema.Schema<A, I, R>
-): Schema.Schema<A, I, R> => {
-  return Schema.declare(
+): Schema.Schema<A & Transferable, I & Transferable, R> =>
+  Schema.declare(
     [item],
     (item) => schemaParse(ParseResult.decodeUnknown(item)),
     (item) => schemaParse(ParseResult.encodeUnknown(item)),
     { identifier: "Transferable" }
   )
-}
 
 const addProxy = <A extends object>(self: A, f: Transferable[typeof symbol]): A & Transferable => {
   return new Proxy(self, {

packages/platform/test/Transferable.test.ts

@@ -2,6 +2,11 @@ import * as Transferable from "@effect/platform/Transferable"
 import { Schema } from "@effect/schema"
 import { assert, describe, test } from "vitest"
 
+const TransferableUint8Array = Transferable.schema(
+  Schema.Uint8ArrayFromSelf,
+  (_) => [_.buffer]
+)
+
 describe("Transferable", () => {
   test("calls symbol", () => {
     class Test implements Transferable.Transferable {
@@ -28,11 +33,32 @@ describe("Transferable", () => {
 
   test("schema Uint8Array", () => {
     const array = new Uint8Array([1, 2, 3])
+    const data = Schema.decodeSync(TransferableUint8Array)(array)
+    assert.deepEqual(Transferable.get(data), [array.buffer])
+  })
+
+  test("schema encode", () => {
     const schema = Transferable.schema(
-      Schema.Uint8ArrayFromSelf,
-      (_) => [_.buffer]
+      Schema.struct({
+        data: Schema.Uint8ArrayFromSelf
+      }),
+      (_) => [_.data.buffer]
     )
-    const data = Schema.decodeSync(schema)(array)
+    const array = new Uint8Array([1, 2, 3])
+    const data = schema({
+      data: array
+    })
+    assert.deepEqual(Transferable.get(data), [array.buffer])
+
+    const encoded = Schema.encodeSync(schema)(data)
+    assert.deepEqual(encoded, {
+      data: array
+    })
+  })
+
+  test("schema encode Uint8Array", () => {
+    const array = new Uint8Array([1, 2, 3])
+    const data = TransferableUint8Array(array)
     assert.deepEqual(Transferable.get(data), [array.buffer])
   })
 })