Fixes #1913

5 files changed, 451 insertions, 233 deletions

diff --git a/src/bun.js/bindings/JSStringDecoder.cpp b/src/bun.js/bindings/JSStringDecoder.cpp
index c73378fdf..96fbc3a57 100644
--- a/src/bun.js/bindings/JSStringDecoder.cpp
+++ b/src/bun.js/bindings/JSStringDecoder.cpp
@@ -21,6 +21,46 @@ static JSC_DECLARE_CUSTOM_GETTER(jsStringDecoder_lastChar);
 static JSC_DECLARE_CUSTOM_GETTER(jsStringDecoder_lastNeed);
 static JSC_DECLARE_CUSTOM_GETTER(jsStringDecoder_lastTotal);
 
+static inline EncodedJSValue jsStringDecoderCast(JSGlobalObject* globalObject, JSValue stringDecoderValue)
+{
+    if (LIKELY(jsDynamicCast<JSStringDecoder*>(stringDecoderValue)))
+        return JSValue::encode(stringDecoderValue);
+
+    auto& vm = globalObject->vm();
+    auto throwScope = DECLARE_THROW_SCOPE(vm);
+
+    if (stringDecoderValue.isEmpty() || stringDecoderValue.isUndefinedOrNull()) {
+        return JSC::JSValue::encode(jsUndefined());
+    }
+
+    if (!stringDecoderValue.isObject()) {
+        return throwThisTypeError(*globalObject, throwScope, JSStringDecoder::info()->className, "write");
+    }
+
+    JSC::JSObject* thisObject = JSC::asObject(stringDecoderValue);
+    JSStringDecoder* castedThis = nullptr;
+    auto clientData = WebCore::clientData(vm);
+    if (JSValue existingDecoderValue = thisObject->getIfPropertyExists(globalObject, clientData->builtinNames().decodePrivateName())) {
+        castedThis = jsDynamicCast<JSStringDecoder*>(existingDecoderValue);
+    }
+
+    if (!castedThis) {
+        BufferEncodingType encoding = BufferEncodingType::utf8;
+        if (JSValue encodingValue = thisObject->getIfPropertyExists(globalObject, clientData->builtinNames().encodingPrivateName())) {
+            if (encodingValue.isString()) {
+                std::optional<BufferEncodingType> opt = parseEnumeration<BufferEncodingType>(*globalObject, encodingValue);
+                if (opt.has_value()) {
+                    encoding = opt.value();
+                }
+            }
+        }
+        castedThis = JSStringDecoder::create(globalObject->vm(), globalObject, reinterpret_cast<Zig::GlobalObject*>(globalObject)->JSStringDecoderStructure(), encoding);
+        thisObject->putDirect(vm, clientData->builtinNames().decodePrivateName(), castedThis, 0);
+    }
+
+    return JSValue::encode(castedThis);
+}
+
 void JSStringDecoder::finishCreation(JSC::VM& vm, JSC::JSGlobalObject* globalObject)
 {
     Base::finishCreation(vm);
@@ -299,7 +339,7 @@ JSC::GCClient::IsoSubspace* JSStringDecoder::subspaceForImpl(JSC::VM& vm)
 
 STATIC_ASSERT_ISO_SUBSPACE_SHARABLE(JSStringDecoderPrototype, JSStringDecoderPrototype::Base);
 
-static inline JSC::EncodedJSValue jsStringDecoderPrototypeFunction_writeBody(JSC::JSGlobalObject* lexicalGlobalObject, JSC::CallFrame* callFrame, typename IDLOperation<JSStringDecoder>::ClassParameter castedThis)
+static inline JSC::EncodedJSValue jsStringDecoderPrototypeFunction_writeBody(JSC::JSGlobalObject* lexicalGlobalObject, JSC::CallFrame* callFrame, JSStringDecoder* castedThis)
 {
     auto& vm = JSC::getVM(lexicalGlobalObject);
     auto throwScope = DECLARE_THROW_SCOPE(vm);
@@ -324,7 +364,7 @@ static inline JSC::EncodedJSValue jsStringDecoderPrototypeFunction_writeBody(JSC
     }
     RELEASE_AND_RETURN(throwScope, JSC::JSValue::encode(castedThis->write(vm, lexicalGlobalObject, reinterpret_cast<uint8_t*>(view->vector()), view->byteLength())));
 }
-static inline JSC::EncodedJSValue jsStringDecoderPrototypeFunction_endBody(JSC::JSGlobalObject* lexicalGlobalObject, JSC::CallFrame* callFrame, typename IDLOperation<JSStringDecoder>::ClassParameter castedThis)
+static inline JSC::EncodedJSValue jsStringDecoderPrototypeFunction_endBody(JSC::JSGlobalObject* lexicalGlobalObject, JSC::CallFrame* callFrame, JSStringDecoder* castedThis)
 {
     auto& vm = JSC::getVM(lexicalGlobalObject);
     auto throwScope = DECLARE_THROW_SCOPE(vm);
@@ -340,7 +380,7 @@ static inline JSC::EncodedJSValue jsStringDecoderPrototypeFunction_endBody(JSC::
     }
     RELEASE_AND_RETURN(throwScope, JSC::JSValue::encode(castedThis->end(vm, lexicalGlobalObject, reinterpret_cast<uint8_t*>(view->vector()), view->byteLength())));
 }
-static inline JSC::EncodedJSValue jsStringDecoderPrototypeFunction_textBody(JSC::JSGlobalObject* lexicalGlobalObject, JSC::CallFrame* callFrame, typename IDLOperation<JSStringDecoder>::ClassParameter castedThis)
+static inline JSC::EncodedJSValue jsStringDecoderPrototypeFunction_textBody(JSC::JSGlobalObject* lexicalGlobalObject, JSC::CallFrame* callFrame, JSStringDecoder* castedThis)
 {
     auto& vm = JSC::getVM(lexicalGlobalObject);
     auto throwScope = DECLARE_THROW_SCOPE(vm);
@@ -366,24 +406,44 @@ static inline JSC::EncodedJSValue jsStringDecoderPrototypeFunction_textBody(JSC:
 static JSC_DEFINE_HOST_FUNCTION(jsStringDecoderPrototypeFunction_write,
     (JSC::JSGlobalObject * globalObject, JSC::CallFrame* callFrame))
 {
-    return IDLOperation<JSStringDecoder>::call<jsStringDecoderPrototypeFunction_writeBody>(*globalObject, *callFrame, "write");
+    JSValue stringDecoderValue = JSValue::decode(jsStringDecoderCast(globalObject, callFrame->thisValue()));
+    if (stringDecoderValue.isEmpty() || !stringDecoderValue.isCell()) {
+        return JSValue::encode(stringDecoderValue);
+    }
+    JSStringDecoder* castedThis = jsCast<JSStringDecoder*>(stringDecoderValue);
+    return jsStringDecoderPrototypeFunction_writeBody(globalObject, callFrame, castedThis);
 }
 static JSC_DEFINE_HOST_FUNCTION(jsStringDecoderPrototypeFunction_end,
     (JSC::JSGlobalObject * globalObject, JSC::CallFrame* callFrame))
 {
-    return IDLOperation<JSStringDecoder>::call<jsStringDecoderPrototypeFunction_endBody>(*globalObject, *callFrame, "end");
+    JSValue stringDecoderValue = JSValue::decode(jsStringDecoderCast(globalObject, callFrame->thisValue()));
+    if (stringDecoderValue.isEmpty() || !stringDecoderValue.isCell()) {
+        return JSValue::encode(stringDecoderValue);
+    }
+    JSStringDecoder* castedThis = jsCast<JSStringDecoder*>(stringDecoderValue);
+    return jsStringDecoderPrototypeFunction_endBody(globalObject, callFrame, castedThis);
 }
 static JSC_DEFINE_HOST_FUNCTION(jsStringDecoderPrototypeFunction_text,
     (JSC::JSGlobalObject * globalObject, JSC::CallFrame* callFrame))
 {
-    return IDLOperation<JSStringDecoder>::call<jsStringDecoderPrototypeFunction_textBody>(*globalObject, *callFrame, "text");
+    JSValue stringDecoderValue = JSValue::decode(jsStringDecoderCast(globalObject, callFrame->thisValue()));
+    if (stringDecoderValue.isEmpty() || !stringDecoderValue.isCell()) {
+        return JSValue::encode(stringDecoderValue);
+    }
+    JSStringDecoder* castedThis = jsCast<JSStringDecoder*>(stringDecoderValue);
+
+    return jsStringDecoderPrototypeFunction_textBody(globalObject, callFrame, castedThis);
 }
 
 static JSC_DEFINE_CUSTOM_GETTER(jsStringDecoder_lastChar, (JSGlobalObject * lexicalGlobalObject, EncodedJSValue thisValue, PropertyName attributeName))
 {
     auto& vm = JSC::getVM(lexicalGlobalObject);
+    JSValue stringDecoderValue = JSValue::decode(jsStringDecoderCast(lexicalGlobalObject, JSValue::decode(thisValue)));
+    if (stringDecoderValue.isEmpty() || !stringDecoderValue.isCell()) {
+        return JSValue::encode(stringDecoderValue);
+    }
+    JSStringDecoder* thisObject = jsCast<JSStringDecoder*>(stringDecoderValue);
     auto throwScope = DECLARE_THROW_SCOPE(vm);
-    JSStringDecoder* thisObject = jsCast<JSStringDecoder*>(JSValue::decode(thisValue));
     auto buffer = ArrayBuffer::createFromBytes(thisObject->m_lastChar, 4, nullptr);
     auto* globalObject = reinterpret_cast<Zig::GlobalObject*>(lexicalGlobalObject);
     JSC::JSUint8Array* uint8Array = JSC::JSUint8Array::create(lexicalGlobalObject, globalObject->JSBufferSubclassStructure(), WTFMove(buffer), 0, 4);
@@ -392,15 +452,23 @@ static JSC_DEFINE_CUSTOM_GETTER(jsStringDecoder_lastChar, (JSGlobalObject * lexi
 static JSC_DEFINE_CUSTOM_GETTER(jsStringDecoder_lastNeed, (JSGlobalObject * lexicalGlobalObject, EncodedJSValue thisValue, PropertyName attributeName))
 {
     auto& vm = JSC::getVM(lexicalGlobalObject);
+    JSValue stringDecoderValue = JSValue::decode(jsStringDecoderCast(lexicalGlobalObject, JSValue::decode(thisValue)));
+    if (stringDecoderValue.isEmpty() || !stringDecoderValue.isCell()) {
+        return JSValue::encode(stringDecoderValue);
+    }
+    JSStringDecoder* thisObject = jsCast<JSStringDecoder*>(stringDecoderValue);
     auto throwScope = DECLARE_THROW_SCOPE(vm);
-    JSStringDecoder* thisObject = jsCast<JSStringDecoder*>(JSValue::decode(thisValue));
     RELEASE_AND_RETURN(throwScope, JSC::JSValue::encode(JSC::jsNumber(thisObject->m_lastNeed)));
 }
 static JSC_DEFINE_CUSTOM_GETTER(jsStringDecoder_lastTotal, (JSGlobalObject * lexicalGlobalObject, EncodedJSValue thisValue, PropertyName attributeName))
 {
     auto& vm = JSC::getVM(lexicalGlobalObject);
+    JSValue stringDecoderValue = JSValue::decode(jsStringDecoderCast(lexicalGlobalObject, JSValue::decode(thisValue)));
+    if (stringDecoderValue.isEmpty() || !stringDecoderValue.isCell()) {
+        return JSValue::encode(stringDecoderValue);
+    }
+    JSStringDecoder* thisObject = jsCast<JSStringDecoder*>(stringDecoderValue);
     auto throwScope = DECLARE_THROW_SCOPE(vm);
-    JSStringDecoder* thisObject = jsCast<JSStringDecoder*>(JSValue::decode(thisValue));
     RELEASE_AND_RETURN(throwScope, JSC::JSValue::encode(JSC::jsNumber(thisObject->m_lastTotal)));
 }
 
@@ -452,13 +520,37 @@ JSC::EncodedJSValue JSStringDecoderConstructor::construct(JSC::JSGlobalObject* l
             }
         }
     }
-    JSStringDecoder* stringDecoder = JSStringDecoder::create(
-        vm, lexicalGlobalObject, reinterpret_cast<Zig::GlobalObject*>(lexicalGlobalObject)->JSStringDecoderStructure(), encoding);
-    return JSC::JSValue::encode(stringDecoder);
+    JSValue thisValue = callFrame->newTarget();
+    auto* globalObject = JSC::jsCast<Zig::GlobalObject*>(lexicalGlobalObject);
+    JSObject* newTarget = asObject(thisValue);
+    auto* constructor = globalObject->JSStringDecoder();
+    Structure* structure = globalObject->JSStringDecoderStructure();
+
+    JSStringDecoder* jsObject = JSStringDecoder::create(
+        vm, lexicalGlobalObject, structure, encoding);
+
+    // StringDecodeer is a Weird one
+    // This is a hack to make express' body-parser work
+    // It does something weird with the prototype
+    // Not exactly a subclass
+    if (constructor != newTarget && callFrame->thisValue().isObject()) {
+        auto clientData = WebCore::clientData(vm);
+        JSObject* thisObject = asObject(callFrame->thisValue());
+
+        thisObject->putDirect(vm, clientData->builtinNames().decodePrivateName(), jsObject, JSC::PropertyAttribute::DontEnum | 0);
+        return JSC::JSValue::encode(thisObject);
+    }
+
+    return JSC::JSValue::encode(jsObject);
 }
 
 void JSStringDecoderConstructor::initializeProperties(VM& vm, JSC::JSGlobalObject* globalObject, JSStringDecoderPrototype* prototype)
 {
+    putDirect(vm, vm.propertyNames->length, jsNumber(1), JSC::PropertyAttribute::ReadOnly | JSC::PropertyAttribute::DontEnum);
+    JSString* nameString = jsNontrivialString(vm, "StringDecoder"_s);
+    m_originalName.set(vm, this, nameString);
+    putDirect(vm, vm.propertyNames->name, nameString, JSC::PropertyAttribute::ReadOnly | JSC::PropertyAttribute::DontEnum);
+    putDirect(vm, vm.propertyNames->prototype, prototype, JSC::PropertyAttribute::ReadOnly | JSC::PropertyAttribute::DontEnum | JSC::PropertyAttribute::DontDelete);
 }
 
 const ClassInfo JSStringDecoderConstructor::s_info = { "StringDecoder"_s, &Base::s_info, nullptr, nullptr, CREATE_METHOD_TABLE(JSStringDecoderConstructor) };
diff --git a/test/bun.js/string-decoder.test.js b/test/bun.js/string-decoder.test.js
index 3d330ffcd..449f35620 100644
--- a/test/bun.js/string-decoder.test.js
+++ b/test/bun.js/string-decoder.test.js
@@ -1,245 +1,301 @@
 import { describe, expect, it } from "bun:test";
 import { withoutAggressiveGC } from "gc";
-var { StringDecoder } = require("string_decoder");
 
-it("require('string_decoder')", async () => {
-  expect((await import("string_decoder")).StringDecoder).toBe(StringDecoder);
-});
+const RealStringDecoder = require("string_decoder").StringDecoder;
 
-it("StringDecoder-utf8", () => {
-  test("utf-8", Buffer.from("$", "utf-8"), "$");
-  test("utf-8", Buffer.from("¢", "utf-8"), "¢");
-  test("utf-8", Buffer.from("€", "utf-8"), "€");
-  test("utf-8", Buffer.from("𤭢", "utf-8"), "𤭢");
-  // A mixed ascii and non-ascii string
-  // Test stolen from deps/v8/test/cctest/test-strings.cc
-  // U+02E4 -> CB A4
-  // U+0064 -> 64
-  // U+12E4 -> E1 8B A4
-  // U+0030 -> 30
-  // U+3045 -> E3 81 85
-  test(
-    "utf-8",
-    Buffer.from([0xcb, 0xa4, 0x64, 0xe1, 0x8b, 0xa4, 0x30, 0xe3, 0x81, 0x85]),
-    "\u02e4\u0064\u12e4\u0030\u3045",
+it("require('string_decoder')", async () => {
+  expect((await import("string_decoder")).StringDecoder).toBe(
+    RealStringDecoder,
   );
 });
 
-it("StringDecoder-ucs-2", () => {
-  test("ucs2", Buffer.from("ababc", "ucs2"), "ababc");
+it("Bun.inspect(StringDecoder)", async () => {
+  expect((await Bun.inspect(RealStringDecoder).length) > 0).toBe(true);
 });
 
-it("StringDecoder-utf16le", () => {
-  test("utf16le", Buffer.from("3DD84DDC", "hex"), "\ud83d\udc4d");
-});
+function FakeStringDecoderCall() {
+  RealStringDecoder.apply(this, arguments);
+}
+require("util").inherits(FakeStringDecoderCall, RealStringDecoder);
 
-it("StringDecoder-utf8-additional", () => {
-  let decoder = new StringDecoder("utf8");
-  expect(decoder.write(Buffer.from("E18B", "hex"))).toBe("");
-  expect(decoder.end()).toBe("\ufffd");
+// extending StringDecoder is not supported
+for (const StringDecoder of [FakeStringDecoderCall, RealStringDecoder]) {
+  describe(StringDecoder.name, () => {
+    it("StringDecoder-utf8", () => {
+      test("utf-8", Buffer.from("$", "utf-8"), "$");
+      test("utf-8", Buffer.from("¢", "utf-8"), "¢");
+      test("utf-8", Buffer.from("€", "utf-8"), "€");
+      test("utf-8", Buffer.from("𤭢", "utf-8"), "𤭢");
+      // A mixed ascii and non-ascii string
+      // Test stolen from deps/v8/test/cctest/test-strings.cc
+      // U+02E4 -> CB A4
+      // U+0064 -> 64
+      // U+12E4 -> E1 8B A4
+      // U+0030 -> 30
+      // U+3045 -> E3 81 85
+      test(
+        "utf-8",
+        Buffer.from([
+          0xcb, 0xa4, 0x64, 0xe1, 0x8b, 0xa4, 0x30, 0xe3, 0x81, 0x85,
+        ]),
+        "\u02e4\u0064\u12e4\u0030\u3045",
+      );
+    });
 
-  decoder = new StringDecoder("utf8");
-  expect(decoder.write(Buffer.from("\ufffd"))).toBe("\ufffd");
-  expect(decoder.end()).toBe("");
+    it("StringDecoder-ucs-2", () => {
+      test("ucs2", Buffer.from("ababc", "ucs2"), "ababc");
+    });
 
-  decoder = new StringDecoder("utf8");
-  expect(decoder.write(Buffer.from("\ufffd\ufffd\ufffd"))).toBe(
-    "\ufffd\ufffd\ufffd",
-  );
-  expect(decoder.end()).toBe("");
+    it("StringDecoder-utf16le", () => {
+      test("utf16le", Buffer.from("3DD84DDC", "hex"), "\ud83d\udc4d");
+    });
 
-  decoder = new StringDecoder("utf8");
-  expect(decoder.write(Buffer.from("EFBFBDE2", "hex"))).toBe("\ufffd");
-  expect(decoder.end()).toBe("\ufffd");
+    it("StringDecoder-utf8-additional", () => {
+      let decoder = new StringDecoder("utf8");
+      expect(decoder.write(Buffer.from("E18B", "hex"))).toBe("");
+      expect(decoder.end()).toBe("\ufffd");
 
-  decoder = new StringDecoder("utf8");
-  expect(decoder.write(Buffer.from("F1", "hex"))).toBe("");
-  expect(decoder.write(Buffer.from("41F2", "hex"))).toBe("\ufffdA");
-  expect(decoder.end()).toBe("\ufffd");
+      decoder = new StringDecoder("utf8");
+      expect(decoder.write(Buffer.from("\ufffd"))).toBe("\ufffd");
+      expect(decoder.end()).toBe("");
 
-  // Additional utf8Text test
-  decoder = new StringDecoder("utf8");
-  expect(decoder.text(Buffer.from([0x41]), 2)).toBe("");
-});
+      decoder = new StringDecoder("utf8");
+      expect(decoder.write(Buffer.from("\ufffd\ufffd\ufffd"))).toBe(
+        "\ufffd\ufffd\ufffd",
+      );
+      expect(decoder.end()).toBe("");
 
-it("StringDecoder-utf16le-additional", () => {
-  // Additional UTF-16LE surrogate pair tests
-  let decoder = new StringDecoder("utf16le");
-  expect(decoder.write(Buffer.from("3DD8", "hex"))).toBe("");
-  expect(decoder.write(Buffer.from("4D", "hex"))).toBe("");
-  expect(decoder.write(Buffer.from("DC", "hex"))).toBe("\ud83d\udc4d");
-  expect(decoder.end()).toBe("");
-
-  decoder = new StringDecoder("utf16le");
-  expect(decoder.write(Buffer.from("3DD8", "hex"))).toBe("");
-  expect(decoder.end()).toBe("\ud83d");
-
-  decoder = new StringDecoder("utf16le");
-  expect(decoder.write(Buffer.from("3DD8", "hex"))).toBe("");
-  expect(decoder.write(Buffer.from("4D", "hex"))).toBe("");
-  expect(decoder.end()).toBe("\ud83d");
-
-  decoder = new StringDecoder("utf16le");
-  expect(decoder.write(Buffer.from("3DD84D", "hex"))).toBe("\ud83d");
-  expect(decoder.end()).toBe("");
-});
+      decoder = new StringDecoder("utf8");
+      expect(decoder.write(Buffer.from("EFBFBDE2", "hex"))).toBe("\ufffd");
+      expect(decoder.end()).toBe("\ufffd");
 
-// Test verifies that StringDecoder will correctly decode the given input
-// buffer with the given encoding to the expected output. It will attempt all
-// possible ways to write() the input buffer, see writeSequences(). The
-// singleSequence allows for easy debugging of a specific sequence which is
-// useful in case of test failures.
-function test(encoding, input, expected, singleSequence) {
-  withoutAggressiveGC(() => {
-    let sequences;
-    if (!singleSequence) {
-      sequences = writeSequences(input.length);
-    } else {
-      sequences = [singleSequence];
-    }
-    sequences.forEach((sequence) => {
-      const decoder = new StringDecoder(encoding);
-      let output = "";
-      sequence.forEach((write) => {
-        output += decoder.write(input.slice(write[0], write[1]));
-      });
-      output += decoder.end();
-      expect(output).toBe(expected);
+      decoder = new StringDecoder("utf8");
+      expect(decoder.write(Buffer.from("F1", "hex"))).toBe("");
+      expect(decoder.write(Buffer.from("41F2", "hex"))).toBe("\ufffdA");
+      expect(decoder.end()).toBe("\ufffd");
+
+      // Additional utf8Text test
+      decoder = new StringDecoder("utf8");
+      expect(decoder.text(Buffer.from([0x41]), 2)).toBe("");
     });
-  });
-}
 
-// writeSequences returns an array of arrays that describes all possible ways a
-// buffer of the given length could be split up and passed to sequential write
-// calls.
-//
-// e.G. writeSequences(3) will return: [
-//   [ [ 0, 3 ] ],
-//   [ [ 0, 2 ], [ 2, 3 ] ],
-//   [ [ 0, 1 ], [ 1, 3 ] ],
-//   [ [ 0, 1 ], [ 1, 2 ], [ 2, 3 ] ]
-// ]
-function writeSequences(length, start, sequence) {
-  if (start === undefined) {
-    start = 0;
-    sequence = [];
-  } else if (start === length) {
-    return [sequence];
-  }
-  let sequences = [];
-  for (let end = length; end > start; end--) {
-    const subSequence = sequence.concat([[start, end]]);
-    const subSequences = writeSequences(length, end, subSequence, sequences);
-    sequences = sequences.concat(subSequences);
-  }
-  return sequences;
-}
+    it("StringDecoder-utf16le-additional", () => {
+      // Additional UTF-16LE surrogate pair tests
+      let decoder = new StringDecoder("utf16le");
+      expect(decoder.write(Buffer.from("3DD8", "hex"))).toBe("");
+      expect(decoder.write(Buffer.from("4D", "hex"))).toBe("");
+      expect(decoder.write(Buffer.from("DC", "hex"))).toBe("\ud83d\udc4d");
+      expect(decoder.end()).toBe("");
 
-describe("StringDecoder.end", () => {
-  const encodings = ["base64", "base64url", "hex", "utf8", "utf16le", "ucs2"];
-
-  const bufs = ["☃💩", "asdf"].map((b) => Buffer.from(b));
-
-  // Also test just arbitrary bytes from 0-15.
-  for (let i = 1; i <= 16; i++) {
-    const bytes = "."
-      .repeat(i - 1)
-      .split(".")
-      .map((_, j) => j + 0x78);
-    bufs.push(Buffer.from(bytes));
-  }
-
-  encodings.forEach(testEncoding);
-
-  testEnd("utf8", Buffer.of(0xe2), Buffer.of(0x61), "\uFFFDa");
-  testEnd("utf8", Buffer.of(0xe2), Buffer.of(0x82), "\uFFFD\uFFFD");
-  testEnd("utf8", Buffer.of(0xe2), Buffer.of(0xe2), "\uFFFD\uFFFD");
-  testEnd("utf8", Buffer.of(0xe2, 0x82), Buffer.of(0x61), "\uFFFDa");
-  testEnd("utf8", Buffer.of(0xe2, 0x82), Buffer.of(0xac), "\uFFFD\uFFFD");
-  testEnd("utf8", Buffer.of(0xe2, 0x82), Buffer.of(0xe2), "\uFFFD\uFFFD");
-  testEnd("utf8", Buffer.of(0xe2, 0x82, 0xac), Buffer.of(0x61), "€a");
-
-  testEnd("utf16le", Buffer.of(0x3d), Buffer.of(0x61, 0x00), "a");
-  testEnd("utf16le", Buffer.of(0x3d), Buffer.of(0xd8, 0x4d, 0xdc), "\u4DD8");
-  testEnd("utf16le", Buffer.of(0x3d, 0xd8), Buffer.of(), "\uD83D");
-  testEnd("utf16le", Buffer.of(0x3d, 0xd8), Buffer.of(0x61, 0x00), "\uD83Da");
-  testEnd(
-    "utf16le",
-    Buffer.of(0x3d, 0xd8),
-    Buffer.of(0x4d, 0xdc),
-    "\uD83D\uDC4D",
-  );
-  testEnd("utf16le", Buffer.of(0x3d, 0xd8, 0x4d), Buffer.of(), "\uD83D");
-  testEnd(
-    "utf16le",
-    Buffer.of(0x3d, 0xd8, 0x4d),
-    Buffer.of(0x61, 0x00),
-    "\uD83Da",
-  );
-  testEnd("utf16le", Buffer.of(0x3d, 0xd8, 0x4d), Buffer.of(0xdc), "\uD83D");
-  testEnd(
-    "utf16le",
-    Buffer.of(0x3d, 0xd8, 0x4d, 0xdc),
-    Buffer.of(0x61, 0x00),
-    "👍a",
-  );
+      decoder = new StringDecoder("utf16le");
+      expect(decoder.write(Buffer.from("3DD8", "hex"))).toBe("");
+      expect(decoder.end()).toBe("\ud83d");
 
-  testEnd("base64", Buffer.of(0x61), Buffer.of(), "YQ==");
-  testEnd("base64", Buffer.of(0x61), Buffer.of(0x61), "YQ==YQ==");
-  testEnd("base64", Buffer.of(0x61, 0x61), Buffer.of(), "YWE=");
-  testEnd("base64", Buffer.of(0x61, 0x61), Buffer.of(0x61), "YWE=YQ==");
-  testEnd("base64", Buffer.of(0x61, 0x61, 0x61), Buffer.of(), "YWFh");
-  testEnd("base64", Buffer.of(0x61, 0x61, 0x61), Buffer.of(0x61), "YWFhYQ==");
-
-  testEnd("base64url", Buffer.of(0x61), Buffer.of(), "YQ");
-  testEnd("base64url", Buffer.of(0x61), Buffer.of(0x61), "YQYQ");
-  testEnd("base64url", Buffer.of(0x61, 0x61), Buffer.of(), "YWE");
-  testEnd("base64url", Buffer.of(0x61, 0x61), Buffer.of(0x61), "YWEYQ");
-  testEnd("base64url", Buffer.of(0x61, 0x61, 0x61), Buffer.of(), "YWFh");
-  testEnd("base64url", Buffer.of(0x61, 0x61, 0x61), Buffer.of(0x61), "YWFhYQ");
-
-  function testEncoding(encoding) {
-    it(encoding + " testbuf", () => {
-      bufs.forEach((buf) => {
-        testBuf(encoding, buf);
-      });
+      decoder = new StringDecoder("utf16le");
+      expect(decoder.write(Buffer.from("3DD8", "hex"))).toBe("");
+      expect(decoder.write(Buffer.from("4D", "hex"))).toBe("");
+      expect(decoder.end()).toBe("\ud83d");
+
+      decoder = new StringDecoder("utf16le");
+      expect(decoder.write(Buffer.from("3DD84D", "hex"))).toBe("\ud83d");
+      expect(decoder.end()).toBe("");
     });
-  }
-
-  function testBuf(encoding, buf) {
-    // Write one byte at a time.
-    let s = new StringDecoder(encoding);
-    let res1 = "";
-    for (let i = 0; i < buf.length; i++) {
-      res1 += s.write(buf.slice(i, i + 1));
+
+    // Test verifies that StringDecoder will correctly decode the given input
+    // buffer with the given encoding to the expected output. It will attempt all
+    // possible ways to write() the input buffer, see writeSequences(). The
+    // singleSequence allows for easy debugging of a specific sequence which is
+    // useful in case of test failures.
+    function test(encoding, input, expected, singleSequence) {
+      withoutAggressiveGC(() => {
+        let sequences;
+        if (!singleSequence) {
+          sequences = writeSequences(input.length);
+        } else {
+          sequences = [singleSequence];
+        }
+        sequences.forEach((sequence) => {
+          const decoder = new StringDecoder(encoding);
+          let output = "";
+          sequence.forEach((write) => {
+            output += decoder.write(input.slice(write[0], write[1]));
+          });
+          output += decoder.end();
+          expect(output).toBe(expected);
+        });
+      });
+    }
+
+    // writeSequences returns an array of arrays that describes all possible ways a
+    // buffer of the given length could be split up and passed to sequential write
+    // calls.
+    //
+    // e.G. writeSequences(3) will return: [
+    //   [ [ 0, 3 ] ],
+    //   [ [ 0, 2 ], [ 2, 3 ] ],
+    //   [ [ 0, 1 ], [ 1, 3 ] ],
+    //   [ [ 0, 1 ], [ 1, 2 ], [ 2, 3 ] ]
+    // ]
+    function writeSequences(length, start, sequence) {
+      if (start === undefined) {
+        start = 0;
+        sequence = [];
+      } else if (start === length) {
+        return [sequence];
+      }
+      let sequences = [];
+      for (let end = length; end > start; end--) {
+        const subSequence = sequence.concat([[start, end]]);
+        const subSequences = writeSequences(
+          length,
+          end,
+          subSequence,
+          sequences,
+        );
+        sequences = sequences.concat(subSequences);
+      }
+      return sequences;
     }
-    res1 += s.end();
-
-    // Write the whole buffer at once.
-    let res2 = "";
-    s = new StringDecoder(encoding);
-    res2 += s.write(buf);
-    res2 += s.end();
-
-    // .toString() on the buffer
-    const res3 = buf.toString(encoding);
-
-    // One byte at a time should match toString
-    expect(res1).toEqual(res3);
-    // All bytes at once should match toString
-    expect(res2).toEqual(res3);
-  }
-
-  function testEnd(encoding, incomplete, next, expected) {
-    it(`${encoding} partial ${JSON.stringify(expected)}`, () => {
-      let res = "";
-      const s = new StringDecoder(encoding);
-      res += s.write(incomplete);
-      res += s.end();
-      res += s.write(next);
-      res += s.end();
-
-      expect(res).toEqual(expected);
+
+    describe("StringDecoder.end", () => {
+      const encodings = [
+        "base64",
+        "base64url",
+        "hex",
+        "utf8",
+        "utf16le",
+        "ucs2",
+      ];
+
+      const bufs = ["☃💩", "asdf"].map((b) => Buffer.from(b));
+
+      // Also test just arbitrary bytes from 0-15.
+      for (let i = 1; i <= 16; i++) {
+        const bytes = "."
+          .repeat(i - 1)
+          .split(".")
+          .map((_, j) => j + 0x78);
+        bufs.push(Buffer.from(bytes));
+      }
+
+      encodings.forEach(testEncoding);
+
+      testEnd("utf8", Buffer.of(0xe2), Buffer.of(0x61), "\uFFFDa");
+      testEnd("utf8", Buffer.of(0xe2), Buffer.of(0x82), "\uFFFD\uFFFD");
+      testEnd("utf8", Buffer.of(0xe2), Buffer.of(0xe2), "\uFFFD\uFFFD");
+      testEnd("utf8", Buffer.of(0xe2, 0x82), Buffer.of(0x61), "\uFFFDa");
+      testEnd("utf8", Buffer.of(0xe2, 0x82), Buffer.of(0xac), "\uFFFD\uFFFD");
+      testEnd("utf8", Buffer.of(0xe2, 0x82), Buffer.of(0xe2), "\uFFFD\uFFFD");
+      testEnd("utf8", Buffer.of(0xe2, 0x82, 0xac), Buffer.of(0x61), "€a");
+
+      testEnd("utf16le", Buffer.of(0x3d), Buffer.of(0x61, 0x00), "a");
+      testEnd(
+        "utf16le",
+        Buffer.of(0x3d),
+        Buffer.of(0xd8, 0x4d, 0xdc),
+        "\u4DD8",
+      );
+      testEnd("utf16le", Buffer.of(0x3d, 0xd8), Buffer.of(), "\uD83D");
+      testEnd(
+        "utf16le",
+        Buffer.of(0x3d, 0xd8),
+        Buffer.of(0x61, 0x00),
+        "\uD83Da",
+      );
+      testEnd(
+        "utf16le",
+        Buffer.of(0x3d, 0xd8),
+        Buffer.of(0x4d, 0xdc),
+        "\uD83D\uDC4D",
+      );
+      testEnd("utf16le", Buffer.of(0x3d, 0xd8, 0x4d), Buffer.of(), "\uD83D");
+      testEnd(
+        "utf16le",
+        Buffer.of(0x3d, 0xd8, 0x4d),
+        Buffer.of(0x61, 0x00),
+        "\uD83Da",
+      );
+      testEnd(
+        "utf16le",
+        Buffer.of(0x3d, 0xd8, 0x4d),
+        Buffer.of(0xdc),
+        "\uD83D",
+      );
+      testEnd(
+        "utf16le",
+        Buffer.of(0x3d, 0xd8, 0x4d, 0xdc),
+        Buffer.of(0x61, 0x00),
+        "👍a",
+      );
+
+      testEnd("base64", Buffer.of(0x61), Buffer.of(), "YQ==");
+      testEnd("base64", Buffer.of(0x61), Buffer.of(0x61), "YQ==YQ==");
+      testEnd("base64", Buffer.of(0x61, 0x61), Buffer.of(), "YWE=");
+      testEnd("base64", Buffer.of(0x61, 0x61), Buffer.of(0x61), "YWE=YQ==");
+      testEnd("base64", Buffer.of(0x61, 0x61, 0x61), Buffer.of(), "YWFh");
+      testEnd(
+        "base64",
+        Buffer.of(0x61, 0x61, 0x61),
+        Buffer.of(0x61),
+        "YWFhYQ==",
+      );
+
+      testEnd("base64url", Buffer.of(0x61), Buffer.of(), "YQ");
+      testEnd("base64url", Buffer.of(0x61), Buffer.of(0x61), "YQYQ");
+      testEnd("base64url", Buffer.of(0x61, 0x61), Buffer.of(), "YWE");
+      testEnd("base64url", Buffer.of(0x61, 0x61), Buffer.of(0x61), "YWEYQ");
+      testEnd("base64url", Buffer.of(0x61, 0x61, 0x61), Buffer.of(), "YWFh");
+      testEnd(
+        "base64url",
+        Buffer.of(0x61, 0x61, 0x61),
+        Buffer.of(0x61),
+        "YWFhYQ",
+      );
+
+      function testEncoding(encoding) {
+        it(encoding + " testbuf", () => {
+          bufs.forEach((buf) => {
+            testBuf(encoding, buf);
+          });
+        });
+      }
+
+      function testBuf(encoding, buf) {
+        // Write one byte at a time.
+        let s = new StringDecoder(encoding);
+        let res1 = "";
+        for (let i = 0; i < buf.length; i++) {
+          res1 += s.write(buf.slice(i, i + 1));
+        }
+        res1 += s.end();
+
+        // Write the whole buffer at once.
+        let res2 = "";
+        s = new StringDecoder(encoding);
+        res2 += s.write(buf);
+        res2 += s.end();
+
+        // .toString() on the buffer
+        const res3 = buf.toString(encoding);
+
+        // One byte at a time should match toString
+        expect(res1).toEqual(res3);
+        // All bytes at once should match toString
+        expect(res2).toEqual(res3);
+      }
+
+      function testEnd(encoding, incomplete, next, expected) {
+        it(`${encoding} partial ${JSON.stringify(expected)}`, () => {
+          let res = "";
+          const s = new StringDecoder(encoding);
+          res += s.write(incomplete);
+          res += s.end();
+          res += s.write(next);
+          res += s.end();
+
+          expect(res).toEqual(expected);
+        });
+      }
     });
-  }
-});
+  });
+}
diff --git a/test/bun.js/third-party/body-parser-test/bun.lockb b/test/bun.js/third-party/body-parser-test/bun.lockb
new file mode 100755
index 000000000..6fdd6d093
--- /dev/null
+++ b/test/bun.js/third-party/body-parser-test/bun.lockb
diff --git a/test/bun.js/third-party/body-parser-test/express-body-parser-test.test.ts b/test/bun.js/third-party/body-parser-test/express-body-parser-test.test.ts
new file mode 100644
index 000000000..905cc4ce2
--- /dev/null
+++ b/test/bun.js/third-party/body-parser-test/express-body-parser-test.test.ts
@@ -0,0 +1,61 @@
+import { test, expect } from "bun:test";
+import express, { Application, Request, Response } from "express";
+import { json } from "body-parser";
+
+// Express uses iconv-lite
+test("iconv works", () => {
+  var iconv = require("iconv-lite");
+
+  // Convert from an encoded buffer to a js string.
+  var str = iconv.decode(
+    Buffer.from([0x68, 0x65, 0x6c, 0x6c, 0x6f]),
+    "win1251",
+  );
+
+  // Convert from a js string to an encoded buffer.
+  var buf = iconv.encode("Sample input string", "win1251");
+  expect(str).toBe("hello");
+  expect(iconv.decode(buf, "win1251")).toBe("Sample input string");
+
+  // Check if encoding is supported
+  expect(iconv.encodingExists("us-ascii")).toBe(true);
+});
+
+// https://github.com/oven-sh/bun/issues/1913
+test("httpServer", async (done) => {
+  // Constants
+  const PORT = 8412;
+
+  // App handlers
+  const app: Application = express();
+  const httpServer = require("http").createServer(app);
+
+  app.on("error", (err) => {
+    done(err);
+  });
+  app.use(json());
+
+  var reached = false;
+  // This throws a TypeError since it uses body-parser.json
+  app.post("/ping", (request: Request, response: Response) => {
+    expect(request.body).toEqual({ hello: "world" });
+    reached = true;
+    response.status(200).send("POST - pong");
+    httpServer.close();
+    done();
+  });
+
+  httpServer.listen(PORT);
+  const resp = await fetch(`http://localhost:${PORT}/ping`, {
+    method: "POST",
+    body: JSON.stringify({ hello: "world" }),
+    headers: {
+      "Content-Type": "application/json",
+    },
+  });
+
+  expect(resp.status).toBe(200);
+  expect(await resp.text()).toBe("POST - pong");
+  expect(reached).toBe(true);
+  done();
+});
diff --git a/test/bun.js/third-party/body-parser-test/package.json b/test/bun.js/third-party/body-parser-test/package.json
new file mode 100644
index 000000000..0dfa98c59
--- /dev/null
+++ b/test/bun.js/third-party/body-parser-test/package.json
@@ -0,0 +1,9 @@
+{
+  "name": "body-parser-test",
+  "version": "1.0.0",
+  "dependencies": {
+    "express": "4.18.2",
+    "body-parser": "1.20.1",
+    "iconv-lite": "0.6.3"
+  }
+}