initial storage examples attempt

examples/storageContext.ts

+import fs from "fs/promises";
+import { Document, VectorStoreIndex, storageContextFromDefaults } from "llamaindex";
+
+async function main() {
+  // Load essay from abramov.txt in Node
+  const essay = await fs.readFile(
+    "node_modules/llamaindex/examples/abramov.txt",
+    "utf-8"
+  );
+
+  // Create Document object with essay
+  const document = new Document({ text: essay });
+
+  // Split text and create embeddings. Store them in a VectorStoreIndex
+  // persist the vector store automatically with the storage context
+  const storageContext = await storageContextFromDefaults({ persistDir: "./storage" });
+  const index = await VectorStoreIndex.fromDocuments([document], storageContext);
+
+  // Query the index
+  const queryEngine = index.asQueryEngine();
+  const response = await queryEngine.query(
+    "What did the author do in college?"
+  );
+
+  // Output response
+  console.log(response.toString());
+
+  // load the index
+  const loadedIndex = await VectorStoreIndex.fromDocuments([], storageContext);
+  const laodedQueryEngine = loadedIndex.asQueryEngine();
+  const loadedResponse = await laodedQueryEngine.query(
+    "What did the author do growing up?"
+  );
+  console.log(loadedResponse.toString());
+}
+
+main().catch(console.error);

packages/core/src/tests/StorageContext.test.ts

+import { existsSync, rmSync } from "fs";
+import { storageContextFromDefaults, StorageContext } from "../storage/StorageContext";
+import { Document } from "../Node";
+import { VectorStoreIndex } from "../indices";
+import { ListIndex } from "../indices";
+
+describe("StorageContext", () => {
+  test("initializes", async () => {
+    const storageContext = await storageContextFromDefaults({ persistDir: "/tmp/test_dir" });
+
+    expect(existsSync("/tmp/test_dir")).toBe(true);
+    expect(storageContext).toBeDefined();
+
+    // cleanup
+    rmSync("/tmp/test_dir", { recursive: true });
+  });
+});