From 365ff3b600534ae05cf2992ceda3e3e9917aaa0c Mon Sep 17 00:00:00 2001
From: Yagiz Nizipli <yagiz@nizipli.com>
Date: Mon, 22 Dec 2025 16:01:47 -0500
Subject: [PATCH] throw appropriate error for non-byob stream mode

---
 src/workerd/api/streams/readable.c++ | 2 +-
 src/wpt/streams-test.ts              | 6 ------
 2 files changed, 1 insertion(+), 7 deletions(-)

diff --git a/src/workerd/api/streams/readable.c++ b/src/workerd/api/streams/readable.c++
index 86237b85cfd..01407efa993 100644
--- a/src/workerd/api/streams/readable.c++
+++ b/src/workerd/api/streams/readable.c++
@@ -352,7 +352,7 @@ ReadableStream::Reader ReadableStream::getReader(
   KJ_IF_SOME(o, options) {
     KJ_IF_SOME(mode, o.mode) {
       JSG_REQUIRE(
-          mode == "byob", RangeError, "mode must be undefined or 'byob' in call to getReader().");
+          mode == "byob", TypeError, "mode must be undefined or 'byob' in call to getReader().");
       // No need to check that the ReadableStream implementation is a byte stream: the first
       // invocation of read() will do that for us and throw if necessary. Also, we should really
       // just support reading non-byte streams with BYOB readers.
diff --git a/src/wpt/streams-test.ts b/src/wpt/streams-test.ts
index 747ac811319..c9152f2dcd8 100644
--- a/src/wpt/streams-test.ts
+++ b/src/wpt/streams-test.ts
@@ -328,7 +328,6 @@ export default {
   'readable-byte-streams/templated.any.js': {
     comment: 'To be investigated',
     expectedFailures: [
-      'ReadableStream with byte source (empty): calling getReader with invalid arguments should throw appropriate errors',
       'ReadableStream with byte source (empty) BYOB reader: canceling via the reader should cause the reader to act closed',
     ],
   },
@@ -438,8 +437,6 @@ export default {
       // TODO(conform): The spec allows error to be called with no argument at all, treating
       // it as undefined, currently we require that undefined is passed explicitly.
       'ReadableStreamDefaultReader closed promise should be rejected with undefined if that is the error',
-      // TODO(conform): The spec expects this to be a TypeError, not a RangeError
-      'getReader() should call ToString() on mode',
     ],
   },
   'readable-streams/floating-point-total-queue-size.any.js': {
@@ -484,8 +481,6 @@ export default {
       "ReadableStream can't be constructed with garbage",
       // TODO(conform): We currently allow the empty type value
       "ReadableStream can't be constructed with an invalid type",
-      // TODO(conform): The spec expects a TypeError here, not a RangeError
-      'default ReadableStream getReader() should only accept mode:undefined',
       // TODO(conform): The spec expects us to call pull an extra time here despite. [Despite what? -NP]
       'ReadableStream: should pull after start, and after every read',
       // TODO(conform): The standard generally anticipates that the closed
@@ -581,7 +576,6 @@ export default {
       'ReadableStream reader (closed via cancel after getting reader): closed should fulfill with undefined',
     ],
     expectedFailures: [
-      'ReadableStream (empty): calling getReader with invalid arguments should throw appropriate errors',
       'ReadableStream reader (closed before getting reader): releasing the lock should cause closed to reject and change identity',
       'ReadableStream reader (closed after getting reader): releasing the lock should cause closed to reject and change identity',
       'ReadableStream reader (closed via cancel after getting reader): releasing the lock should cause closed to reject and change identity',