feat: modular domain driven boilerplate

platform/database/accessor.ts

@@ -0,0 +1,48 @@
+import { Collection, type CollectionOptions, type Db, type Document, type MongoClient } from "mongodb";
+
+import { container } from "./container.ts";
+
+export function getDatabaseAccessor<TSchemas extends Record<string, Document>>(
+  database: string,
+): DatabaseAccessor<TSchemas> {
+  let instance: Db | undefined;
+  return {
+    get db(): Db {
+      if (instance === undefined) {
+        instance = this.client.db(database);
+      }
+      return instance;
+    },
+    get client(): MongoClient {
+      return container.get("mongo");
+    },
+    collection<TSchema extends keyof TSchemas>(
+      name: TSchema,
+      options?: CollectionOptions,
+    ): Collection<TSchemas[TSchema]> {
+      return this.db.collection<TSchemas[TSchema]>(name.toString(), options);
+    },
+  };
+}
+
+export type DatabaseAccessor<TSchemas extends Record<string, Document>> = {
+  /**
+   * Database for given accessor.
+   */
+  db: Db;
+
+  /**
+   * Lazy loaded mongo client.
+   */
+  client: MongoClient;
+
+  /**
+   * Returns a reference to a MongoDB Collection. If it does not exist it will be created implicitly.
+   *
+   * Collection namespace validation is performed server-side.
+   *
+   * @param name    - Collection name we wish to access.
+   * @param options - Optional settings for the command.
+   */
+  collection<TSchema extends keyof TSchemas>(name: TSchema, options?: CollectionOptions): Collection<TSchemas[TSchema]>;
+};