should be it

external/duckdb/extension/json/json_functions/json_valid.cpp

@@ -0,0 +1,27 @@
+#include "json_executors.hpp"
+
+namespace duckdb {
+
+static void ValidFunction(DataChunk &args, ExpressionState &state, Vector &result) {
+	auto &lstate = JSONFunctionLocalState::ResetAndGet(state);
+	auto alc = lstate.json_allocator->GetYYAlc();
+	auto &inputs = args.data[0];
+	UnaryExecutor::Execute<string_t, bool>(inputs, result, args.size(), [&](string_t input) {
+		return JSONCommon::ReadDocumentUnsafe(input, JSONCommon::READ_FLAG, alc);
+	});
+}
+
+static void GetValidFunctionInternal(ScalarFunctionSet &set, const LogicalType &input_type) {
+	set.AddFunction(ScalarFunction("json_valid", {input_type}, LogicalType::BOOLEAN, ValidFunction, nullptr, nullptr,
+	                               nullptr, JSONFunctionLocalState::Init));
+}
+
+ScalarFunctionSet JSONFunctions::GetValidFunction() {
+	ScalarFunctionSet set("json_valid");
+	GetValidFunctionInternal(set, LogicalType::VARCHAR);
+	GetValidFunctionInternal(set, LogicalType::JSON());
+
+	return set;
+}
+
+} // namespace duckdb