ci(node): run examples in CI (#1796)

This is done as setup for a PR that will fix the OpenAI dependency
issue.

 * [x] FTS examples
 * [x] Setup mock openai
 * [x] Ran `npm audit fix`
 * [x] sentences embeddings test
 * [x] Double check formatting of docs examples

nodejs/examples/embedding.test.ts

@@ -0,0 +1,96 @@
+// SPDX-License-Identifier: Apache-2.0
+// SPDX-FileCopyrightText: Copyright The LanceDB Authors
+import { expect, test } from "@jest/globals";
+// --8<-- [start:imports]
+import * as lancedb from "@lancedb/lancedb";
+import "@lancedb/lancedb/embedding/openai";
+import { LanceSchema, getRegistry, register } from "@lancedb/lancedb/embedding";
+import { EmbeddingFunction } from "@lancedb/lancedb/embedding";
+import { type Float, Float32, Utf8 } from "apache-arrow";
+// --8<-- [end:imports]
+import { withTempDirectory } from "./util.ts";
+
+const openAiTest = process.env.OPENAI_API_KEY == null ? test.skip : test;
+
+openAiTest("openai embeddings", async () => {
+  await withTempDirectory(async (databaseDir) => {
+    // --8<-- [start:openai_embeddings]
+    const db = await lancedb.connect(databaseDir);
+    const func = getRegistry()
+      .get("openai")
+      ?.create({ model: "text-embedding-ada-002" }) as EmbeddingFunction;
+
+    const wordsSchema = LanceSchema({
+      text: func.sourceField(new Utf8()),
+      vector: func.vectorField(),
+    });
+    const tbl = await db.createEmptyTable("words", wordsSchema, {
+      mode: "overwrite",
+    });
+    await tbl.add([{ text: "hello world" }, { text: "goodbye world" }]);
+
+    const query = "greetings";
+    const actual = (await tbl.search(query).limit(1).toArray())[0];
+    // --8<-- [end:openai_embeddings]
+    expect(actual).toHaveProperty("text");
+  });
+});
+
+test("custom embedding function", async () => {
+  await withTempDirectory(async (databaseDir) => {
+    // --8<-- [start:embedding_function]
+    const db = await lancedb.connect(databaseDir);
+
+    @register("my_embedding")
+    class MyEmbeddingFunction extends EmbeddingFunction<string> {
+      toJSON(): object {
+        return {};
+      }
+      ndims() {
+        return 3;
+      }
+      embeddingDataType(): Float {
+        return new Float32();
+      }
+      async computeQueryEmbeddings(_data: string) {
+        // This is a placeholder for a real embedding function
+        return [1, 2, 3];
+      }
+      async computeSourceEmbeddings(data: string[]) {
+        // This is a placeholder for a real embedding function
+        return Array.from({ length: data.length }).fill([
+          1, 2, 3,
+        ]) as number[][];
+      }
+    }
+
+    const func = new MyEmbeddingFunction();
+
+    const data = [{ text: "pepperoni" }, { text: "pineapple" }];
+
+    // Option 1: manually specify the embedding function
+    const table = await db.createTable("vectors", data, {
+      embeddingFunction: {
+        function: func,
+        sourceColumn: "text",
+        vectorColumn: "vector",
+      },
+      mode: "overwrite",
+    });
+
+    // Option 2: provide the embedding function through a schema
+
+    const schema = LanceSchema({
+      text: func.sourceField(new Utf8()),
+      vector: func.vectorField(),
+    });
+
+    const table2 = await db.createTable("vectors2", data, {
+      schema,
+      mode: "overwrite",
+    });
+    // --8<-- [end:embedding_function]
+    expect(await table.countRows()).toBe(2);
+    expect(await table2.countRows()).toBe(2);
+  });
+});