From e08702a235fbd8f4c0a9998cda44074fba8f605b Mon Sep 17 00:00:00 2001
From: Linus Groh <mail@linusgroh.de>
Date: Sun, 27 Jun 2021 20:58:43 +0100
Subject: [PATCH] LibJS: Add content type check to
 InitializeTypedArrayFromTypedArray()

Resolves a FIXME.
---
 Userland/Libraries/LibJS/Runtime/ErrorTypes.h               | 1 +
 Userland/Libraries/LibJS/Runtime/TypedArray.cpp             | 6 +++++-
 .../Libraries/LibJS/Tests/builtins/TypedArray/TypedArray.js | 2 +-
 3 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/Userland/Libraries/LibJS/Runtime/ErrorTypes.h b/Userland/Libraries/LibJS/Runtime/ErrorTypes.h
index fd25ea2077..1dbc7c71c8 100644
--- a/Userland/Libraries/LibJS/Runtime/ErrorTypes.h
+++ b/Userland/Libraries/LibJS/Runtime/ErrorTypes.h
@@ -154,6 +154,7 @@
     M(ThisIsAlreadyInitialized, "|this| is already initialized")                                                                        \
     M(ToObjectNullOrUndefined, "ToObject on null or undefined")                                                                         \
     M(ToPrimitiveReturnedObject, "Can't convert {} to primitive with hint \"{}\", its @@toPrimitive method returned an object")         \
+    M(TypedArrayContentTypeMismatch, "Can't create {} from {}")                                                                         \
     M(TypedArrayInvalidBufferLength, "Invalid buffer length for {}: must be a multiple of {}, got {}")                                  \
     M(TypedArrayInvalidByteOffset, "Invalid byte offset for {}: must be a multiple of {}, got {}")                                      \
     M(TypedArrayOutOfRangeByteOffset, "Typed array byte offset {} is out of range for buffer with length {}")                           \
diff --git a/Userland/Libraries/LibJS/Runtime/TypedArray.cpp b/Userland/Libraries/LibJS/Runtime/TypedArray.cpp
index f42bc1fa3b..867a34a90a 100644
--- a/Userland/Libraries/LibJS/Runtime/TypedArray.cpp
+++ b/Userland/Libraries/LibJS/Runtime/TypedArray.cpp
@@ -103,7 +103,6 @@ static void initialize_typed_array_from_typed_array(GlobalObject& global_object,
         return;
     }
 
-    // FIXME: 17.c If src_array.[[ContentType]] != dest_array.[[ContentType]], throw a TypeError exception.
     auto data = ArrayBuffer::create(global_object, byte_length.value());
 
     if (src_data->is_detached()) {
@@ -111,6 +110,11 @@ static void initialize_typed_array_from_typed_array(GlobalObject& global_object,
         return;
     }
 
+    if (src_array.content_type() != dest_array.content_type()) {
+        vm.throw_exception<TypeError>(global_object, ErrorType::TypedArrayContentTypeMismatch, dest_array.class_name(), src_array.class_name());
+        return;
+    }
+
     dest_array.set_viewed_array_buffer(data);
     dest_array.set_byte_length(byte_length.value());
     dest_array.set_byte_offset(0);
diff --git a/Userland/Libraries/LibJS/Tests/builtins/TypedArray/TypedArray.js b/Userland/Libraries/LibJS/Tests/builtins/TypedArray/TypedArray.js
index a9fe088c52..65642f2ce7 100644
--- a/Userland/Libraries/LibJS/Tests/builtins/TypedArray/TypedArray.js
+++ b/Userland/Libraries/LibJS/Tests/builtins/TypedArray/TypedArray.js
@@ -158,7 +158,7 @@ test("typed array from TypedArray", () => {
     BIGINT_TYPED_ARRAYS.forEach(T => {
         expect(() => {
             const newTypedArray = new T(u8Array);
-        }).toThrowWithMessage(TypeError, "Cannot convert number to BigInt");
+        }).toThrowWithMessage(TypeError, `Can't create ${T.name} from Uint8Array`);
 
         const newBigIntTypedArray = new T(bigU64Array);
         expect(newBigIntTypedArray[0]).toBe(1n);