feat: introduce setLogger method

lib/index.ts

@@ -48,6 +48,8 @@ const addon = bindings<{
   databaseClose(db: NativeDatabase): void;
 
   signalTokenize(value: string): Array<string>;
+
+  setLogger(fn: (code: string, message: string) => void): void;
 }>(ROOT_DIR);
 
 export type RunResult = {
@@ -587,4 +589,12 @@ export default class Database {
   }
 }
 
-export { Database };
+function setLogger(fn: (code: string, message: string) => void): void {
+  if (typeof fn !== 'function') {
+    throw new TypeError('Invalid value');
+  }
+
+  return addon.setLogger(fn);
+}
+
+export { Database, setLogger };

src/addon.cc

@@ -74,6 +74,48 @@ static Napi::Value SignalTokenize(const Napi::CallbackInfo& info) {
   return result;
 }
 
+// Global Settings
+
+thread_local Napi::Reference<Napi::Function> logger_fn_;
+
+static void LoggerWrapper(void* _ctx, int code, const char* msg) {
+  if (logger_fn_.IsEmpty()) {
+    return;
+  }
+
+  auto env = logger_fn_.Env();
+  Napi::HandleScope scope(env);
+
+#define CODE_STR(NAME) \
+  case NAME:           \
+    code_name = #NAME; \
+    break;
+
+  const char* code_name;
+  switch (code) {
+    SQLITE_ERROR_ENUM(CODE_STR)
+    default:
+      code_name = "unknown";
+      break;
+  }
+
+#undef CODE_STR
+
+  logger_fn_.Value().Call({
+      Napi::String::New(env, code_name),
+      Napi::String::New(env, msg),
+  });
+}
+
+static void SetLogger(const Napi::CallbackInfo& info) {
+  auto callback = info[0].As<Napi::Function>();
+  assert(callback.IsFunction());
+
+  logger_fn_.Reset(callback, 1);
+
+  sqlite3_config(SQLITE_CONFIG_LOG, LoggerWrapper);
+}
+
 // Utils
 
 Napi::Error FormatError(Napi::Env env, const char* format, ...) {
@@ -856,6 +898,7 @@ Napi::Object Init(Napi::Env env, Napi::Object exports) {
 
   Database::Init(env, exports);
   Statement::Init(env, exports);
+  exports["setLogger"] = Napi::Function::New(env, &SetLogger);
   exports["signalTokenize"] = Napi::Function::New(env, &SignalTokenize);
   return exports;
 }

test/memory.test.ts

@@ -1,6 +1,6 @@
 import { describe, expect, test, beforeEach, afterEach } from 'vitest';
 
-import Database from '../lib/index.js';
+import Database, { setLogger } from '../lib/index.js';
 
 const rows = [
   {
@@ -180,6 +180,21 @@ test('persistent statement recompilation', () => {
   });
 });
 
+test('setLogger should log on statement recompilation', () => {
+  const messages = new Array<{ code: string; message: string }>();
+  setLogger((code, message) => messages.push({ code, message }));
+
+  const stmt = db.prepare('SELECT * FROM t', { persistent: true });
+
+  db.exec(`ALTER TABLE t ADD COLUMN d TEXT DEFAULT 'hello'`);
+
+  expect(stmt.get()).not.toBeUndefined();
+
+  expect(messages).toHaveLength(1);
+  expect(messages[0]?.code).toEqual('SQLITE_SCHEMA');
+  expect(messages[0]?.message).toMatch(/database schema has changed/);
+});
+
 describe('list parameters', () => {
   test('correct count', () => {
     expect(db.prepare('SELECT * FROM t WHERE a > ?').get([2])).toEqual(rows[2]);