Merge pull request #2862 from armanbilge/fix/chunk-js-interop

`Chunk` <-> JS `Uint8Array` conversion should respect offset/length
typelevel · Mar 29, 2022 · 652b021 · 652b021
2 parents 6993229 + d07eafa
commit 652b021
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Showing 2 changed files with 19 additions and 1 deletion.
diff --git a/core/js/src/main/scala/fs2/ChunkRuntimePlatform.scala b/core/js/src/main/scala/fs2/ChunkRuntimePlatform.scala
@@ -52,6 +52,8 @@ trait ChunkCompanionRuntimePlatform { self: Chunk.type =>
     byteBuffer(TypedArrayBuffer.wrap(buffer))
 
   def uint8Array(array: Uint8Array): Chunk[Byte] =
-    jsArrayBuffer(array.buffer)
+    byteBuffer(
+      TypedArrayBuffer.wrap(array.buffer, array.byteOffset, array.byteLength)
+    )
 
 }
diff --git a/core/js/src/test/scala/fs2/ChunkRuntimePlatformSuite.scala b/core/js/src/test/scala/fs2/ChunkRuntimePlatformSuite.scala
@@ -25,6 +25,9 @@ import org.scalacheck.Arbitrary
 import org.scalacheck.Gen
 import org.scalacheck.Prop.forAll
 
+import scala.scalajs.js.typedarray.Int8Array
+import scala.scalajs.js.typedarray.Uint8Array
+
 class ChunkRuntimePlatformSuite extends Fs2Suite {
   override def scalaCheckTestParameters =
     super.scalaCheckTestParameters
@@ -50,6 +53,19 @@ class ChunkRuntimePlatformSuite extends Fs2Suite {
           assertEquals(Chunk.uint8Array(c.toUint8Array), c)
         }
       }
+      property("Uint8Array conversion respects offset and length") {
+        forAll[(Chunk[Byte], Int, Int), Unit](for {
+          chunk <- genChunk
+          offset <- Gen.chooseNum(0, chunk.size)
+          length <- Gen.chooseNum(0, chunk.size - offset)
+        } yield (chunk, offset, length)) { case (chunk, offset, length) =>
+          val buffer = chunk.toJSArrayBuffer
+          assertEquals(
+            Chunk.uint8Array(new Uint8Array(buffer, offset, length)),
+            Chunk.array(new Int8Array(buffer, offset, length).toArray)
+          )
+        }
+      }
     }
 
   testByteChunk(byteBufferChunkGenerator, "ByteBuffer")