getDatabaseFile specifies MIME type and works with db in subfolder

src/client.ts

@@ -275,9 +275,23 @@ export class SQLocal {
 	};
 
 	getDatabaseFile = async () => {
-		const opfs = await navigator.storage.getDirectory();
-		const fileHandle = await opfs.getFileHandle(this.databasePath);
-		return await fileHandle.getFile();
+		const path = this.databasePath.split(/[\\/]/).filter((part) => part !== '');
+		const fileName = path.pop();
+
+		if (!fileName) {
+			throw new Error('Failed to parse the database file name.');
+		}
+
+		let dirHandle = await navigator.storage.getDirectory();
+		for (let dirName of path)
+			dirHandle = await dirHandle.getDirectoryHandle(dirName);
+
+		const fileHandle = await dirHandle.getFileHandle(fileName);
+		const file = await fileHandle.getFile();
+
+		return new File([file], fileName, {
+			type: 'application/x-sqlite3',
+		});
 	};
 
 	overwriteDatabaseFile = async (

test/get-database-file.test.ts

@@ -0,0 +1,38 @@
+import { describe, expect, it } from 'vitest';
+import { SQLocal } from '../src/index';
+
+describe('getDatabaseFile', () => {
+	const fileName = 'get-database-file-test.sqlite3';
+	const paths = [[], [''], ['top'], ['one', 'two']];
+
+	it('should return the requested database file', async () => {
+		for (let path of paths) {
+			const databasePath = [...path, fileName].join('/');
+			const { sql, getDatabaseFile } = new SQLocal(databasePath);
+
+			await sql`CREATE TABLE nums (num REAL NOT NULL)`;
+			const file = await getDatabaseFile();
+
+			expect(file).toBeInstanceOf(File);
+			expect(file.name).toBe(fileName);
+			expect(file.size).toBe(16384);
+			expect(file.type).toBe('application/x-sqlite3');
+
+			let dirHandle = await navigator.storage.getDirectory();
+
+			for (let dirName of path) {
+				if (dirName === '') continue;
+				dirHandle = await dirHandle.getDirectoryHandle(dirName);
+			}
+
+			await dirHandle.removeEntry(fileName);
+		}
+	});
+
+	it('should throw when requested database has not been created', async () => {
+		const { getDatabaseFile } = new SQLocal(fileName);
+		expect(async () => await getDatabaseFile()).rejects.toThrowError(
+			'A requested file or directory could not be found at the time an operation was processed.'
+		);
+	});
+});