speed it up a little more

4 files changed, 290 insertions, 119 deletions

diff --git a/src/bun.js/bindings/JSBuffer.cpp b/src/bun.js/bindings/JSBuffer.cpp
index a6c735af7..2ce07617a 100644
--- a/src/bun.js/bindings/JSBuffer.cpp
+++ b/src/bun.js/bindings/JSBuffer.cpp
@@ -1350,6 +1350,73 @@ static inline JSC::EncodedJSValue jsBufferPrototypeFunction_swap64Body(JSC::JSGl
     return JSC::JSValue::encode(castedThis);
 }
 
+static inline JSC::EncodedJSValue jsBufferToString(JSC::VM& vm, JSC::JSGlobalObject* lexicalGlobalObject, JSC::JSUint8Array* castedThis, size_t offset, size_t length, WebCore::BufferEncodingType encoding)
+{
+    auto scope = DECLARE_THROW_SCOPE(vm);
+
+    if (UNLIKELY(length == 0)) {
+        RELEASE_AND_RETURN(scope, JSC::JSValue::encode(JSC::jsEmptyString(vm)));
+    }
+
+    JSC::EncodedJSValue ret = 0;
+
+    switch (encoding) {
+    case WebCore::BufferEncodingType::latin1: {
+        LChar* data = nullptr;
+        auto str = String::createUninitialized(length, data);
+        memcpy(data, reinterpret_cast<const char*>(castedThis->typedVector() + offset), length);
+        return JSC::JSValue::encode(JSC::jsString(vm, WTFMove(str)));
+    }
+
+    case WebCore::BufferEncodingType::ucs2:
+    case WebCore::BufferEncodingType::utf16le: {
+        UChar* data = nullptr;
+        size_t u16length = length / 2;
+        if (u16length == 0) {
+            return JSC::JSValue::encode(JSC::jsEmptyString(vm));
+        } else {
+            auto str = String::createUninitialized(u16length, data);
+            // always zero out the last byte of the string incase the buffer is not a multiple of 2
+            data[u16length - 1] = 0;
+            memcpy(data, reinterpret_cast<const char*>(castedThis->typedVector() + offset), length);
+            return JSC::JSValue::encode(JSC::jsString(vm, WTFMove(str)));
+        }
+
+        break;
+    }
+
+    case WebCore::BufferEncodingType::ascii: {
+        // ascii: we always know the length
+        // so we might as well allocate upfront
+        LChar* data = nullptr;
+        auto str = String::createUninitialized(length, data);
+        Bun__encoding__writeLatin1(castedThis->typedVector() + offset, length, data, length, static_cast<uint8_t>(encoding));
+        return JSC::JSValue::encode(JSC::jsString(vm, WTFMove(str)));
+    }
+
+    case WebCore::BufferEncodingType::buffer:
+    case WebCore::BufferEncodingType::utf8:
+    case WebCore::BufferEncodingType::base64:
+    case WebCore::BufferEncodingType::base64url:
+    case WebCore::BufferEncodingType::hex: {
+        ret = Bun__encoding__toString(castedThis->typedVector() + offset, length, lexicalGlobalObject, static_cast<uint8_t>(encoding));
+        break;
+    }
+    default: {
+        throwTypeError(lexicalGlobalObject, scope, "Unsupported encoding? This shouldn't happen"_s);
+        break;
+    }
+    }
+
+    JSC::JSValue retValue = JSC::JSValue::decode(ret);
+    if (UNLIKELY(!retValue.isString())) {
+        scope.throwException(lexicalGlobalObject, retValue);
+        return JSC::JSValue::encode(jsUndefined());
+    }
+
+    RELEASE_AND_RETURN(scope, JSC::JSValue::encode(retValue));
+}
+
 static inline JSC::EncodedJSValue jsBufferPrototypeFunction_toStringBody(JSC::JSGlobalObject* lexicalGlobalObject, JSC::CallFrame* callFrame, typename IDLOperation<JSArrayBufferView>::ClassParameter castedThis)
 {
     auto& vm = JSC::getVM(lexicalGlobalObject);
@@ -1361,8 +1428,6 @@ static inline JSC::EncodedJSValue jsBufferPrototypeFunction_toStringBody(JSC::JS
     if (length == 0)
         return JSC::JSValue::encode(JSC::jsEmptyString(vm));
 
-    auto scope = DECLARE_THROW_SCOPE(vm);
-
     switch (callFrame->argumentCount()) {
     case 0: {
         break;
@@ -1374,6 +1439,8 @@ static inline JSC::EncodedJSValue jsBufferPrototypeFunction_toStringBody(JSC::JS
         if (arg1.value().isString()) {
             std::optional<BufferEncodingType> encoded = parseEnumeration<BufferEncodingType>(*lexicalGlobalObject, arg1.value());
             if (!encoded) {
+                auto scope = DECLARE_THROW_SCOPE(vm);
+
                 throwTypeError(lexicalGlobalObject, scope, "Invalid encoding"_s);
                 return JSC::JSValue::encode(jsUndefined());
             }
@@ -1389,6 +1456,8 @@ static inline JSC::EncodedJSValue jsBufferPrototypeFunction_toStringBody(JSC::JS
         JSC::JSValue arg2 = callFrame->uncheckedArgument(1);
         int32_t ioffset = arg2.toInt32(lexicalGlobalObject);
         if (ioffset < 0) {
+            auto scope = DECLARE_THROW_SCOPE(vm);
+
             throwTypeError(lexicalGlobalObject, scope, "Offset must be a positive integer"_s);
             return JSC::JSValue::encode(jsUndefined());
         }
@@ -1406,61 +1475,33 @@ static inline JSC::EncodedJSValue jsBufferPrototypeFunction_toStringBody(JSC::JS
 
     length -= std::min(offset, length);
 
-    if (UNLIKELY(length == 0)) {
-        RELEASE_AND_RETURN(scope, JSC::JSValue::encode(JSC::jsEmptyString(vm)));
-    }
+    return jsBufferToString(vm, lexicalGlobalObject, castedThis, offset, length, encoding);
+}
 
-    JSC::EncodedJSValue ret = 0;
+// DOMJIT makes it slower! TODO: investigate why
+// JSC_DECLARE_JIT_OPERATION_WITHOUT_WTF_INTERNAL(jsBufferPrototypeToStringWithoutTypeChecks, JSValue, (JSC::JSGlobalObject * lexicalGlobalObject, JSC::JSUint8Array* thisValue, JSC::JSString* encodingValue));
 
-    switch (encoding) {
-    case WebCore::BufferEncodingType::latin1: {
-        LChar* data = nullptr;
-        auto str = String::createUninitialized(length, data);
-        memcpy(data, reinterpret_cast<const char*>(castedThis->typedVector() + offset), length);
-        ret = JSC::JSValue::encode(JSC::jsString(vm, WTFMove(str)));
-        break;
-    }
+// JSC_DEFINE_JIT_OPERATION(jsBufferPrototypeToStringWithoutTypeChecks, JSValue, (JSC::JSGlobalObject * lexicalGlobalObject, JSUint8Array* thisValue, JSString* encodingValue))
+// {
+//     VM& vm = JSC::getVM(lexicalGlobalObject);
+//     IGNORE_WARNINGS_BEGIN("frame-address")
+//     CallFrame* callFrame = DECLARE_CALL_FRAME(vm);
+//     IGNORE_WARNINGS_END
+//     JSC::JITOperationPrologueCallFrameTracer tracer(vm, callFrame);
 
-    case WebCore::BufferEncodingType::ucs2:
-    case WebCore::BufferEncodingType::utf16le: {
-        UChar* data = nullptr;
-        size_t u16length = length / 2;
-        if (u16length == 0) {
-            ret = JSC::JSValue::encode(JSC::jsEmptyString(vm));
-        } else {
-            auto str = String::createUninitialized(u16length, data);
-            // always zero out the last byte of the string incase the buffer is not a multiple of 2
-            data[u16length - 1] = 0;
-            memcpy(data, reinterpret_cast<const char*>(castedThis->typedVector() + offset), length);
-            ret = JSC::JSValue::encode(JSC::jsString(vm, WTFMove(str)));
-        }
+//     std::optional<BufferEncodingType> encoded = parseEnumeration<BufferEncodingType>(*lexicalGlobalObject, encodingValue);
+//     if (!encoded) {
+//         auto scope = DECLARE_THROW_SCOPE(vm);
 
-        break;
-    }
+//         throwTypeError(lexicalGlobalObject, scope, "Invalid encoding"_s);
+//         return {};
+//     }
 
-    case WebCore::BufferEncodingType::buffer:
-    case WebCore::BufferEncodingType::utf8:
-    case WebCore::BufferEncodingType::ascii:
-    case WebCore::BufferEncodingType::base64:
-    case WebCore::BufferEncodingType::base64url:
-    case WebCore::BufferEncodingType::hex: {
-        ret = Bun__encoding__toString(castedThis->typedVector() + offset, length, lexicalGlobalObject, static_cast<uint8_t>(encoding));
-        break;
-    }
-    default: {
-        throwTypeError(lexicalGlobalObject, scope, "Unsupported encoding? This shouldn't happen"_s);
-        break;
-    }
-    }
+//     auto encoding = encoded.value();
 
-    JSC::JSValue retValue = JSC::JSValue::decode(ret);
-    if (UNLIKELY(!retValue.isString())) {
-        scope.throwException(lexicalGlobalObject, retValue);
-        return JSC::JSValue::encode(jsUndefined());
-    }
+//     return JSValue::decode(jsBufferToString(vm, lexicalGlobalObject, thisValue, 0, thisValue->byteLength(), encoding));
+// }
 
-    RELEASE_AND_RETURN(scope, JSC::JSValue::encode(retValue));
-}
 static inline JSC::EncodedJSValue jsBufferPrototypeFunction_writeBody(JSC::JSGlobalObject* lexicalGlobalObject, JSC::CallFrame* callFrame, typename IDLOperation<JSArrayBufferView>::ClassParameter castedThis)
 {
     auto& vm = JSC::getVM(lexicalGlobalObject);
diff --git a/src/bun.js/webcore/encoding.zig b/src/bun.js/webcore/encoding.zig
index 3172966ef..8a6e3224b 100644
--- a/src/bun.js/webcore/encoding.zig
+++ b/src/bun.js/webcore/encoding.zig
@@ -795,43 +795,20 @@ pub const Encoder = struct {
 
         switch (comptime encoding) {
             .ascii => {
-                var to = allocator.alloc(u8, len) catch return ZigString.init("Out of memory").toErrorInstance(global);
-                var complete = to;
-                var remain = input;
-
-                if (comptime bun.Environment.enableSIMD) {
-                    const vector_size = 16;
-                    // https://zig.godbolt.org/z/qezsY8T3W
-                    var remain_in_u64 = remain[0 .. remain.len - (remain.len % vector_size)];
-                    var to_in_u64 = to[0 .. to.len - (to.len % vector_size)];
-                    var remain_as_u64 = std.mem.bytesAsSlice(u64, remain_in_u64);
-                    var to_as_u64 = std.mem.bytesAsSlice(u64, to_in_u64);
-                    const inner_vector_size = vector_size / 8;
-                    const end_vector_len = @min(remain_as_u64.len, to_as_u64.len);
-                    remain_as_u64 = remain_as_u64[0..end_vector_len];
-                    to_as_u64 = to_as_u64[0..end_vector_len];
-                    const end_ptr = remain_as_u64.ptr + remain_as_u64.len;
-                    // using the pointer instead of the length is super important for the codegen
-                    while (end_ptr != remain_as_u64.ptr) {
-                        const buf = @as(@Vector(inner_vector_size, u64), remain_as_u64[0..inner_vector_size].*);
-                        const mask = @splat(inner_vector_size, @as(u64, 0x7f7f7f7f7f7f7f7f));
-                        to_as_u64[0..inner_vector_size].* = buf & mask;
-
-                        remain_as_u64 = remain_as_u64[inner_vector_size..];
-                        to_as_u64 = to_as_u64[inner_vector_size..];
-                    }
-                    remain = remain[remain_in_u64.len..];
-                    to = to[to_in_u64.len..];
+                if (bun.simdutf.validate.ascii(input)) {
+                    return ZigString.init(input).toValueGC(global);
                 }
 
-                const end_ptr = to.ptr + to.len;
-                while (to.ptr != end_ptr) {
-                    to[0] = @as(u8, @truncate(u7, remain[0]));
-                    to = to[1..];
-                    remain = remain[1..];
+                if (input.len < 512) {
+                    var buf: [512]u8 = undefined;
+                    var to = buf[0..input.len];
+                    strings.copyLatin1IntoASCII(to, input);
+                    return ZigString.init(to).toValueGC(global);
                 }
 
-                return ZigString.init(complete).toExternalValue(global);
+                var to = allocator.alloc(u8, len) catch return ZigString.init("Out of memory").toErrorInstance(global);
+                strings.copyLatin1IntoASCII(to, input);
+                return ZigString.init(to).toExternalValue(global);
             },
             .latin1 => {
                 var to = allocator.alloc(u8, len) catch return ZigString.init("Out of memory").toErrorInstance(global);
@@ -884,7 +861,7 @@ pub const Encoder = struct {
         }
     }
 
-    pub fn writeU8(input: [*]const u8, len: usize, to: [*]u8, to_len: usize, comptime encoding: JSC.Node.Encoding) i64 {
+    pub fn writeU8(input: [*]const u8, len: usize, to_ptr: [*]u8, to_len: usize, comptime encoding: JSC.Node.Encoding) i64 {
         if (len == 0 or to_len == 0)
             return 0;
 
@@ -898,39 +875,42 @@ pub const Encoder = struct {
         switch (comptime encoding) {
             JSC.Node.Encoding.buffer => {
                 const written = @min(len, to_len);
-                @memcpy(to, input, written);
+                @memcpy(to_ptr, input, written);
 
                 return @intCast(i64, written);
             },
             .latin1, .ascii => {
                 const written = @min(len, to_len);
-                @memcpy(to, input, written);
 
-                // Hoping this gets auto vectorized
-                for (to[0..written]) |c, i| {
-                    to[i] = @as(u8, @truncate(u7, c));
+                var to = to_ptr[0..written];
+                var remain = input[0..written];
+
+                if (bun.simdutf.validate.ascii(remain)) {
+                    @memcpy(to.ptr, remain.ptr, written);
+                } else {
+                    strings.copyLatin1IntoASCII(to, remain);
                 }
 
                 return @intCast(i64, written);
             },
             .utf8 => {
                 // need to encode
-                return @intCast(i64, strings.copyLatin1IntoUTF8(to[0..to_len], []const u8, input[0..len]).written);
+                return @intCast(i64, strings.copyLatin1IntoUTF8(to_ptr[0..to_len], []const u8, input[0..len]).written);
             },
             // encode latin1 into UTF16
             JSC.Node.Encoding.ucs2, JSC.Node.Encoding.utf16le => {
                 if (to_len < 2)
                     return 0;
 
-                if (std.mem.isAligned(@ptrToInt(to), @alignOf([*]u16))) {
+                if (std.mem.isAligned(@ptrToInt(to_ptr), @alignOf([*]u16))) {
                     var buf = input[0..len];
 
-                    var output = @ptrCast([*]u16, @alignCast(@alignOf(u16), to))[0 .. to_len / 2];
+                    var output = @ptrCast([*]u16, @alignCast(@alignOf(u16), to_ptr))[0 .. to_len / 2];
                     var written = strings.copyLatin1IntoUTF16([]u16, output, []const u8, buf).written;
                     return written * 2;
                 } else {
                     var buf = input[0..len];
-                    var output = @ptrCast([*]align(1) u16, to)[0 .. to_len / 2];
+                    var output = @ptrCast([*]align(1) u16, to_ptr)[0 .. to_len / 2];
 
                     var written = strings.copyLatin1IntoUTF16([]align(1) u16, output, []const u8, buf).written;
                     return written * 2;
@@ -938,7 +918,7 @@ pub const Encoder = struct {
             },
 
             JSC.Node.Encoding.hex => {
-                return @intCast(i64, strings.decodeHexToBytes(to[0..to_len], u8, input[0..len]));
+                return @intCast(i64, strings.decodeHexToBytes(to_ptr[0..to_len], u8, input[0..len]));
             },
 
             JSC.Node.Encoding.base64url => {
@@ -952,12 +932,12 @@ pub const Encoder = struct {
                     slice = slice[0 .. slice.len - 1];
                 }
 
-                const wrote = bun.base64.decodeURLSafe(to[0..to_len], slice).written;
+                const wrote = bun.base64.decodeURLSafe(to_ptr[0..to_len], slice).written;
                 return @intCast(i64, wrote);
             },
 
             JSC.Node.Encoding.base64 => {
-                return @intCast(i64, bun.base64.decode(to[0..to_len], input[0..len]).written);
+                return @intCast(i64, bun.base64.decode(to_ptr[0..to_len], input[0..len]).written);
             },
             // else => return 0,
         }
diff --git a/src/string_immutable.zig b/src/string_immutable.zig
index 68c22b773..63dd70090 100644
--- a/src/string_immutable.zig
+++ b/src/string_immutable.zig
@@ -1012,6 +1012,53 @@ pub inline fn copyU16IntoU8(output_: []u8, comptime InputType: type, input_: Inp
 
 const strings = @This();
 
+pub fn copyLatin1IntoASCII(dest: []u8, src: []const u8) void {
+    var remain = src;
+    var to = dest;
+
+    const non_ascii_offset = strings.firstNonASCII(remain) orelse @truncate(u32, remain.len);
+    if (non_ascii_offset > 0) {
+        @memcpy(to.ptr, remain.ptr, non_ascii_offset);
+        remain = remain[non_ascii_offset..];
+        to = to[non_ascii_offset..];
+
+        // ascii fast path
+        if (remain.len == 0) {
+            return;
+        }
+    }
+
+    if (to.len >= 16 and bun.Environment.enableSIMD) {
+        const vector_size = 16;
+        // https://zig.godbolt.org/z/qezsY8T3W
+        var remain_in_u64 = remain[0 .. remain.len - (remain.len % vector_size)];
+        var to_in_u64 = to[0 .. to.len - (to.len % vector_size)];
+        var remain_as_u64 = std.mem.bytesAsSlice(u64, remain_in_u64);
+        var to_as_u64 = std.mem.bytesAsSlice(u64, to_in_u64);
+        const end_vector_len = @min(remain_as_u64.len, to_as_u64.len);
+        remain_as_u64 = remain_as_u64[0..end_vector_len];
+        to_as_u64 = to_as_u64[0..end_vector_len];
+        const end_ptr = remain_as_u64.ptr + remain_as_u64.len;
+        // using the pointer instead of the length is super important for the codegen
+        while (end_ptr != remain_as_u64.ptr) {
+            const buf = remain_as_u64[0];
+            // this gets auto-vectorized
+            const mask = @as(u64, 0x7f7f7f7f7f7f7f7f);
+            to_as_u64[0] = buf & mask;
+
+            remain_as_u64 = remain_as_u64[1..];
+            to_as_u64 = to_as_u64[1..];
+        }
+        remain = remain[remain_in_u64.len..];
+        to = to[to_in_u64.len..];
+    }
+
+    for (to) |*to_byte| {
+        to_byte.* = @as(u8, @truncate(u7, remain[0]));
+        remain = remain[1..];
+    }
+}
+
 /// Convert a UTF-8 string to a UTF-16 string IF there are any non-ascii characters
 /// If there are no non-ascii characters, this returns null
 /// This is intended to be used for strings that go to JavaScript
@@ -1023,28 +1070,23 @@ pub fn toUTF16Alloc(allocator: std.mem.Allocator, bytes: []const u8, comptime fa
         if (bytes.len == 0)
             return &[_]u16{};
         use_simdutf: {
-            const validated = bun.simdutf.validate.with_errors.ascii(bytes);
-            if (validated.status == .success)
+            if (bun.simdutf.validate.ascii(bytes))
                 return null;
 
-            const offset = @truncate(u32, validated.count);
-
-            const trimmed = bun.simdutf.trim.utf8(bytes[offset..]);
+            const trimmed = bun.simdutf.trim.utf8(bytes);
 
             if (trimmed.len == 0)
                 break :use_simdutf;
 
             const out_length = bun.simdutf.length.utf16.from.utf8.le(trimmed);
 
-            if (out_length != trimmed.len)
+            if (out_length == 0)
                 break :use_simdutf;
 
-            var out = try allocator.alloc(u16, out_length + offset);
+            var out = try allocator.alloc(u16, out_length);
             log("toUTF16 {d} UTF8 -> {d} UTF16", .{ bytes.len, out_length });
-            if (offset > 0)
-                strings.copyU8IntoU16(out[0..offset], bytes[0..offset]);
 
-            const result = bun.simdutf.convert.utf8.to.utf16.with_errors.le(trimmed, out[offset..]);
+            const result = bun.simdutf.convert.utf8.to.utf16.with_errors.le(trimmed, out);
             switch (result.status) {
                 .success => {
                     return out;
@@ -1055,7 +1097,7 @@ pub fn toUTF16Alloc(allocator: std.mem.Allocator, bytes: []const u8, comptime fa
                         return error.InvalidByteSequence;
                     }
 
-                    first_non_ascii = @truncate(u32, result.count) + offset;
+                    first_non_ascii = @truncate(u32, result.count);
                     output_ = std.ArrayList(u16){
                         .items = out[0..first_non_ascii.?],
                         .capacity = out.len,
diff --git a/test/bun.js/text-decoder.test.js b/test/bun.js/text-decoder.test.js
index be3f8421b..da0497464 100644
--- a/test/bun.js/text-decoder.test.js
+++ b/test/bun.js/text-decoder.test.js
@@ -42,7 +42,118 @@ describe("TextDecoder", () => {
     gcTrace(true);
     expect(decoder.decode(new Uint8Array([0x41, 0x42, 0x43]))).toBe("ABC");
     gcTrace(true);
-    const result = [72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33];
+
+    // hit the SIMD code path
+    const result = [
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
+    ];
     gcTrace(true);
     expect(decoder.decode(Uint8Array.from(result))).toBe(String.fromCharCode(...result));
     gcTrace(true);
@@ -51,19 +162,16 @@ describe("TextDecoder", () => {
   it("should decode unicode text", () => {
     const decoder = new TextDecoder();
     gcTrace(true);
-    var text = `❤️ Red Heart`;
-
-    const bytes = [226, 157, 164, 239, 184, 143, 32, 82, 101, 100, 32, 72, 101, 97, 114, 116];
-    const decoded = decoder.decode(Uint8Array.from(bytes));
-    expect(decoder.encoding).toBe("utf-8");
+    const inputBytes = [226, 157, 164, 239, 184, 143, 32, 82, 101, 100, 32, 72, 101, 97, 114, 116];
+    for (var repeat = 1; repeat < 100; repeat++) {
+      var text = `❤️ Red Heart`.repeat(repeat);
 
-    gcTrace(true);
-
-    for (let i = 0; i < text.length; i++) {
-      expect(decoded.charCodeAt(i)).toBe(text.charCodeAt(i));
+      var bytes = Array.from({ length: repeat }, () => inputBytes).flat();
+      var decoded = decoder.decode(Uint8Array.from(bytes));
+      expect(decoder.encoding).toBe("utf-8");
+      expect(decoded).toBe(text);
+      gcTrace(true);
     }
-    expect(decoded).toHaveLength(text.length);
-    gcTrace(true);
   });
 
   describe("typedArrays", () => {