Add deepseek.ts to src/llms with corresponding unit tests. Updates fa… (#4613)

Co-authored-by: kartik-mem0 <kartik.labhshetwar@mem0.ai>

mem0-ts/src/oss/src/llms/deepseek.ts

@@ -0,0 +1,43 @@
+import { OpenAILLM } from "./openai";
+import { LLMConfig, Message } from "../types";
+import { LLMResponse } from "./base";
+
+export class DeepSeekLLM extends OpenAILLM {
+  constructor(config: LLMConfig) {
+    const apiKey = config.apiKey || process.env.DEEPSEEK_API_KEY;
+    if (!apiKey) {
+      throw new Error("DeepSeek API key is required");
+    }
+    super({
+      ...config,
+      apiKey,
+      baseURL:
+        config.baseURL ||
+        process.env.DEEPSEEK_API_BASE ||
+        "https://api.deepseek.com",
+      model: config.model || "deepseek-chat",
+    });
+  }
+
+  async generateResponse(
+    messages: Message[],
+    responseFormat?: { type: string },
+    tools?: any[],
+  ): Promise<string | LLMResponse> {
+    try {
+      return await super.generateResponse(messages, responseFormat, tools);
+    } catch (err) {
+      const message = err instanceof Error ? err.message : String(err);
+      throw new Error(`DeepSeek LLM failed: ${message}`);
+    }
+  }
+
+  async generateChat(messages: Message[]): Promise<LLMResponse> {
+    try {
+      return await super.generateChat(messages);
+    } catch (err) {
+      const message = err instanceof Error ? err.message : String(err);
+      throw new Error(`DeepSeek LLM failed: ${message}`);
+    }
+  }
+}

mem0-ts/src/oss/src/utils/factory.ts

@@ -35,6 +35,7 @@ import { LangchainEmbedder } from "../embeddings/langchain";
 import { LangchainVectorStore } from "../vector_stores/langchain";
 import { AzureAISearch } from "../vector_stores/azure_ai_search";
 import { PGVector } from "../vector_stores/pgvector";
+import { DeepSeekLLM } from "../llms/deepseek";
 
 export class EmbedderFactory {
   static create(provider: string, config: EmbeddingConfig): Embedder {
@@ -82,6 +83,8 @@ export class LLMFactory {
         return new MistralLLM(config);
       case "langchain":
         return new LangchainLLM(config);
+      case "deepseek":
+        return new DeepSeekLLM(config);
       default:
         throw new Error(`Unsupported LLM provider: ${provider}`);
     }

mem0-ts/src/oss/tests/deepseek.test.ts

@@ -0,0 +1,124 @@
+/// <reference types="jest" />
+/**
+ * DeepSeek LLM — unit tests (mocked OpenAI).
+ */
+
+import { DeepSeekLLM } from "../src/llms/deepseek";
+
+const mockCreate = jest.fn();
+
+jest.mock("openai", () => {
+  return jest.fn().mockImplementation(() => ({
+    chat: { completions: { create: mockCreate } },
+  }));
+});
+
+describe("DeepSeekLLM (unit)", () => {
+  beforeEach(() => mockCreate.mockClear());
+
+  it("throws when no API key is provided", () => {
+    const original = process.env.DEEPSEEK_API_KEY;
+    delete process.env.DEEPSEEK_API_KEY;
+    try {
+      expect(() => new DeepSeekLLM({})).toThrow("DeepSeek API key is required");
+    } finally {
+      if (original !== undefined) process.env.DEEPSEEK_API_KEY = original;
+    }
+  });
+
+  it("generateResponse() returns a text response", async () => {
+    mockCreate.mockResolvedValueOnce({
+      choices: [
+        {
+          message: {
+            content: "Hello, world!",
+            role: "assistant",
+            tool_calls: null,
+          },
+        },
+      ],
+    });
+
+    const llm = new DeepSeekLLM({ apiKey: "test-key" });
+    const result = await llm.generateResponse([
+      { role: "user", content: "Hi" },
+    ]);
+
+    expect(mockCreate).toHaveBeenCalledTimes(1);
+    expect(result).toBe("Hello, world!");
+  });
+
+  it("generateResponse() handles tool calls", async () => {
+    mockCreate.mockResolvedValueOnce({
+      choices: [
+        {
+          message: {
+            content: "",
+            role: "assistant",
+            tool_calls: [
+              {
+                function: {
+                  name: "get_weather",
+                  arguments: '{"city": "London"}',
+                },
+              },
+            ],
+          },
+        },
+      ],
+    });
+
+    const llm = new DeepSeekLLM({ apiKey: "test-key" });
+    const result = await llm.generateResponse(
+      [{ role: "user", content: "What is the weather?" }],
+      undefined,
+      [{ type: "function", function: { name: "get_weather" } }],
+    );
+
+    expect(result).toEqual({
+      content: "",
+      role: "assistant",
+      toolCalls: [{ name: "get_weather", arguments: '{"city": "London"}' }],
+    });
+  });
+
+  it("generateResponse() wraps API errors with a clear message", async () => {
+    mockCreate.mockRejectedValueOnce(new Error("Connection refused"));
+
+    const llm = new DeepSeekLLM({ apiKey: "test-key" });
+
+    await expect(
+      llm.generateResponse([{ role: "user", content: "Hi" }]),
+    ).rejects.toThrow("DeepSeek LLM failed: Connection refused");
+  });
+
+  it("generateChat() returns LLMResponse shape", async () => {
+    mockCreate.mockResolvedValueOnce({
+      choices: [
+        {
+          message: { content: "I can help with that.", role: "assistant" },
+        },
+      ],
+    });
+
+    const llm = new DeepSeekLLM({ apiKey: "test-key" });
+    const result = await llm.generateChat([
+      { role: "user", content: "Help me" },
+    ]);
+
+    expect(result).toEqual({
+      content: "I can help with that.",
+      role: "assistant",
+    });
+  });
+
+  it("generateChat() wraps API errors with a clear message", async () => {
+    mockCreate.mockRejectedValueOnce(new Error("Timeout"));
+
+    const llm = new DeepSeekLLM({ apiKey: "test-key" });
+
+    await expect(
+      llm.generateChat([{ role: "user", content: "Hi" }]),
+    ).rejects.toThrow("DeepSeek LLM failed: Timeout");
+  });
+});

mem0-ts/src/oss/tests/factory.unit.test.ts

@@ -87,6 +87,11 @@ jest.mock("../src/llms/lmstudio", () => ({
     .fn()
     .mockImplementation((config) => ({ type: "lmstudio-llm", config })),
 }));
+jest.mock("../src/llms/deepseek", () => ({
+  DeepSeekLLM: jest
+    .fn()
+    .mockImplementation((config) => ({ type: "deepseek-llm", config })),
+}));
 
 jest.mock("../src/vector_stores/qdrant", () => ({
   Qdrant: jest
@@ -200,6 +205,7 @@ describe("LLMFactory", () => {
     ["mistral"],
     ["langchain"],
     ["lmstudio"],
+    ["deepseek"],
   ])("creates LLM for provider '%s'", (provider) => {
     expect(() => LLMFactory.create(provider, dummyLLMConfig)).not.toThrow();
   });