chore: implement getDylibPath and update docs

Author: DominicGBauer

packages/powersync-op-sqlite/README.md

@@ -68,6 +68,40 @@ const factory = new OPSqliteOpenFactory({
 });
 ```
 
+### Loading SQLite extensions
+
+To load additional SQLite extensions include the `extensions` option in `sqliteOptions` which expects an array of objects with a `path` and an `entryPoint`:
+
+```js
+sqliteOptions: {
+  extensions: [
+      { path: libPath, entryPoint: 'sqlite3_powersync_init' }
+  ]
+}
+```
+
+More info can be found in the [OP-SQLite docs](https://op-engineering.github.io/op-sqlite/docs/api/#loading-extensions).
+
+Example usage:
+
+```ts
+let libPath: string
+if (Platform.OS === 'ios') {
+  libPath = getDylibPath('powersync-sqlite-core', 'powersync-sqlite-core')
+} else {
+  libPath = 'libpowersync';
+}
+
+const factory = new OPSqliteOpenFactory({
+  dbFilename: 'sqlite.db',
+  sqliteOptions: {
+    extensions: [
+        { path: libPath, entryPoint: 'sqlite3_powersync_init' }
+    ]
+  }
+});
+```
+
 ## Native Projects
 
 This package uses native libraries. Create native Android and iOS projects (if not created already) by running:

packages/powersync-op-sqlite/src/db/OPSqliteAdapter.ts

@@ -1,8 +1,21 @@
-import { BaseObserver, DBAdapter, DBAdapterListener, DBLockOptions, QueryResult, Transaction } from '@powersync/common';
-import { ANDROID_DATABASE_PATH, IOS_LIBRARY_PATH, open, type DB } from '@op-engineering/op-sqlite';
+import {
+  BaseObserver,
+  DBAdapter,
+  DBAdapterListener,
+  DBLockOptions,
+  QueryResult,
+  Transaction
+} from '@powersync/common';
+import {
+  ANDROID_DATABASE_PATH,
+  getDylibPath,
+  IOS_LIBRARY_PATH,
+  open,
+  type DB
+} from '@op-engineering/op-sqlite';
 import Lock from 'async-lock';
 import { OPSQLiteConnection } from './OPSQLiteConnection';
-import { NativeModules, Platform } from 'react-native';
+import { Platform } from 'react-native';
 import { SqliteOptions } from './SqliteOptions';
 
 /**
@@ -135,8 +148,7 @@ export class OPSQLiteDBAdapter extends BaseObserver<DBAdapterListener> implement
 
   private loadPowerSyncExtension(DB: DB) {
     if (Platform.OS === 'ios') {
-      const bundlePath: string = NativeModules.PowerSyncOpSqlite.getBundlePath();
-      const libPath = `${bundlePath}/Frameworks/powersync-sqlite-core.framework/powersync-sqlite-core`;
+      const libPath = getDylibPath('powersync-sqlite-core', 'powersync-sqlite-core')
       DB.loadExtension(libPath, 'sqlite3_powersync_init');
     } else {
       DB.loadExtension('libpowersync', 'sqlite3_powersync_init');