add configuration options for DuckDB class (#200)

* add configuration options for DuckDB class

* Refactor DuckDB init statements.

---------

Co-authored-by: Jeffrey Heer <[email protected]>

Author: ricksmit3000

packages/duckdb/src/DuckDB.js

@@ -3,19 +3,23 @@ import { mergeBuffers } from './merge-buffers.js';
 
 const TEMP_DIR = '.duckdb';
 
-const CONFIG = [
+const DEFAULT_INIT_STATEMENTS = [
   `PRAGMA temp_directory='${TEMP_DIR}'`,
   `INSTALL arrow`,
   `INSTALL httpfs`,
   `LOAD arrow`,
   `LOAD httpfs`
-];
+].join(';\n');
 
 export class DuckDB {
-  constructor(path = ':memory:') {
-    this.db = new duckdb.Database(path);
+  constructor(
+    path = ':memory:',
+    config = {},
+    initStatements = DEFAULT_INIT_STATEMENTS
+  ) {
+    this.db = new duckdb.Database(path, config);
     this.con = this.db.connect();
-    this.exec(CONFIG.join(';\n'));
+    this.exec(initStatements);
   }
 
   close() {