Document better but still throw

Author: simolus3

packages/common/src/client/SQLOpenFactory.ts

@@ -7,6 +7,9 @@ export interface SQLOpenOptions {
   dbFilename: string;
   /**
    * Directory where the database file is located.
+   * 
+   * When set, the directory must exist when the database is opened, it will
+   * not be created automatically.
    */
   dbLocation?: string;
 

packages/node/src/db/BetterSQLite3DBAdapter.ts

@@ -54,6 +54,19 @@ export class BetterSQLite3DBAdapter extends BaseObserver<DBAdapterListener> impl
   async initialize() {
     let dbFilePath = this.options.dbFilename;
     if (this.options.dbLocation !== undefined) {
+      // Make sure the dbLocation exists, we get a TypeError from better-sqlite3 otherwise.
+      let directoryExists = false;
+      try {
+        const stat = await fs.stat(this.options.dbLocation);
+        directoryExists = stat.isDirectory();
+      } catch (_) {
+        // If we can't even stat, the directory won't be accessible to SQLite either.
+      }
+
+      if (!directoryExists) {
+        throw new Error(`The dbLocation directory at "${this.options.dbLocation}" does not exist. Please create it before opening the PowerSync database!`);
+      }
+
       // SQLite reports a misuse error when the target directory of the database doesn't exist,
       // so create it now before we access the database.
       await fs.mkdir(this.options.dbLocation, { recursive: true });

packages/node/tests/PowerSyncDatabase.test.ts

@@ -93,26 +93,20 @@ databaseTest('can watch tables', async ({ database }) => {
   await expect.poll(() => fn).toHaveBeenCalledTimes(2);
 });
 
-tempDirectoryTest('automatically creates directory', async ({ tmpdir }) => {
+tempDirectoryTest('throws error if target directory does not exist', async ({ tmpdir }) => {
   const directory = path.join(tmpdir, 'some', 'nested', 'location', 'that', 'does', 'not', 'exist');
 
-  const database = new PowerSyncDatabase({
-    schema: AppSchema,
-    database: {
-      dbFilename: 'test.db',
-      dbLocation: directory,
-      readWorkerCount: 2
-    }
-  });
-
-  // Make sure there's a write to the file
-  await database.writeLock((conn) => conn.execute('pragma user_version = 2'));
-
-  // Make sure the file is actually created in the right location
-  await fs.access(
-    path.join(directory, 'test.db'),
-    fs.constants.F_OK | fs.constants.R_OK | fs.constants.W_OK
-  );
+  expect(async () => {
+    const database = new PowerSyncDatabase({
+      schema: AppSchema,
+      database: {
+        dbFilename: 'test.db',
+        dbLocation: directory,
+        readWorkerCount: 2
+      }
+    });
+    await database.waitForReady();
+  }).rejects.toThrowError(/The dbLocation directory at ".+" does not exist/);
 });
 
 databaseTest.skip('can watch queries', async ({ database }) => {