fix: Add imports and batchFileAdapter implementation.

src/persist/batchFileAdapter.ts

@@ -0,0 +1,28 @@
+import { FileAdapter } from './fileAdapter';
+import { BatchAdapter } from './batchAdapter';
+
+/**
+ * FileAdapter is the file adapter for Casbin.
+ * It can load policy from file or save policy to file.
+ */
+export class BatchFileAdapter extends FileAdapter implements BatchAdapter {
+  /**
+   * FileAdapter is the constructor for FileAdapter.
+   * @param {string} filePath filePath the path of the policy file.
+   */
+  constructor(filePath: string) {
+    super(filePath);
+  }
+
+  // addPolicies adds policy rules to the storage.
+  // This is part of the Auto-Save feature.
+  public async addPolicies(sec: string, ptype: string, rules: string[][]): Promise<void> {
+    throw new Error('not implemented');
+  }
+
+  // removePolicies removes policy rules from the storage.
+  // This is part of the Auto-Save feature.
+  public async removePolicies(sec: string, ptype: string, rules: string[][]): Promise<void> {
+    throw new Error('not implemented');
+  }
+}

src/persist/index.ts

@@ -5,3 +5,5 @@ export * from './helper';
 export * from './watcher';
 export * from './filteredAdapter';
 export * from './defaultFilteredAdapter';
+export * from './batchAdapter';
+export * from './batchFileAdapter';