community[minor],docs[minor]: Add ChromeAI chat model

libs/langchain-community/.gitignore

@@ -518,6 +518,10 @@ chat_models/cloudflare_workersai.cjs
 chat_models/cloudflare_workersai.js
 chat_models/cloudflare_workersai.d.ts
 chat_models/cloudflare_workersai.d.cts
+chat_models/chrome_ai.cjs
+chat_models/chrome_ai.js
+chat_models/chrome_ai.d.ts
+chat_models/chrome_ai.d.cts
 chat_models/deepinfra.cjs
 chat_models/deepinfra.js
 chat_models/deepinfra.d.ts

libs/langchain-community/langchain.config.js

@@ -166,6 +166,7 @@ export const config = {
     "chat_models/bedrock": "chat_models/bedrock/index",
     "chat_models/bedrock/web": "chat_models/bedrock/web",
     "chat_models/cloudflare_workersai": "chat_models/cloudflare_workersai",
+    "chat_models/chrome_ai": "chat_models/chrome_ai",
     "chat_models/deepinfra": "chat_models/deepinfra",
     "chat_models/fireworks": "chat_models/fireworks",
     "chat_models/friendli": "chat_models/friendli",

libs/langchain-community/package.json

@@ -1870,6 +1870,15 @@
       "import": "./chat_models/cloudflare_workersai.js",
       "require": "./chat_models/cloudflare_workersai.cjs"
     },
+    "./chat_models/chrome_ai": {
+      "types": {
+        "import": "./chat_models/chrome_ai.d.ts",
+        "require": "./chat_models/chrome_ai.d.cts",
+        "default": "./chat_models/chrome_ai.d.ts"
+      },
+      "import": "./chat_models/chrome_ai.js",
+      "require": "./chat_models/chrome_ai.cjs"
+    },
     "./chat_models/deepinfra": {
       "types": {
         "import": "./chat_models/deepinfra.d.ts",
@@ -3555,6 +3564,10 @@
     "chat_models/cloudflare_workersai.js",
     "chat_models/cloudflare_workersai.d.ts",
     "chat_models/cloudflare_workersai.d.cts",
+    "chat_models/chrome_ai.cjs",
+    "chat_models/chrome_ai.js",
+    "chat_models/chrome_ai.d.ts",
+    "chat_models/chrome_ai.d.cts",
     "chat_models/deepinfra.cjs",
     "chat_models/deepinfra.js",
     "chat_models/deepinfra.d.ts",

libs/langchain-community/src/chat_models/chrome_ai.ts

@@ -0,0 +1,181 @@
+import {
+  SimpleChatModel,
+  type BaseChatModelParams,
+} from "@langchain/core/language_models/chat_models";
+import type { BaseLanguageModelCallOptions } from "@langchain/core/language_models/base";
+import { CallbackManagerForLLMRun } from "@langchain/core/callbacks/manager";
+import { BaseMessage, AIMessageChunk } from "@langchain/core/messages";
+import { ChatGenerationChunk } from "@langchain/core/outputs";
+
+export interface AI {
+  canCreateTextSession(): Promise<AIModelAvailability>;
+  createTextSession(options?: AITextSessionOptions): Promise<AITextSession>;
+  defaultTextSessionOptions(): Promise<AITextSessionOptions>;
+}
+
+export interface AITextSession {
+  prompt(input: string): Promise<string>;
+  promptStreaming(input: string): ReadableStream;
+  destroy(): void;
+  clone(): AITextSession;
+}
+
+export interface AITextSessionOptions {
+  topK: number;
+  temperature: number;
+}
+
+export enum AIModelAvailability {
+  Readily = "readily",
+  AfterDownload = "after-download",
+  No = "no",
+}
+
+export interface ChromeAIInputs extends BaseChatModelParams {
+  topK?: number;
+  temperature?: number;
+}
+
+export interface ChromeAICallOptions extends BaseLanguageModelCallOptions {}
+
+function formatPrompt(messages: BaseMessage[]): string {
+  return messages
+    .map((message) => {
+      if (typeof message.content !== "string") {
+        throw new Error(
+          "ChatChromeAI does not support non-string message content."
+        );
+      }
+      return `<${message._getType()}>\n${
+        message.content
+      }\n</${message._getType()}>`;
+    })
+    .join("\n");
+}
+
+/**
+ * To use this model you need to have the `Built-in AI Early Preview Program`
+ * for Chrome. You can find more information about the program here:
+ * @link https://developer.chrome.com/docs/ai/built-in
+ *
+ * @example
+ * ```typescript
+ * // Initialize the ChatChromeAI model.
+ * const model = new ChatChromeAI({
+ *   temperature: 0.5, // Optional. Default is 0.5.
+ *   topK: 40, // Optional. Default is 40.
+ * });
+ *
+ * // Call the model with a message and await the response.
+ * const response = await model.invoke([
+ *   new HumanMessage({ content: "My name is John." }),
+ * ]);
+ * ```
+ */
+export class ChatChromeAI extends SimpleChatModel<ChromeAICallOptions> {
+  session?: AITextSession;
+
+  temperature = 0.5;
+
+  topK = 40;
+
+  static lc_name() {
+    return "ChatChromeAI";
+  }
+
+  constructor(inputs: ChromeAIInputs) {
+    super(inputs);
+    this.temperature = inputs.temperature ?? this.temperature;
+    this.topK = inputs.topK ?? this.topK;
+  }
+
+  _llmType() {
+    return "chrome-ai";
+  }
+
+  /**
+   * Initialize the model. This method must be called before calling `.invoke()`.
+   */
+  async initialize() {
+    if (typeof window === "undefined") {
+      throw new Error("ChatChromeAI can only be used in the browser.");
+    }
+
+    const ai: AI = (window as any).ai;
+    const canCreateTextSession = await ai.canCreateTextSession();
+    if (canCreateTextSession === AIModelAvailability.No) {
+      throw new Error("The AI model is not available.");
+    } else if (canCreateTextSession === AIModelAvailability.AfterDownload) {
+      throw new Error("The AI model is not yet downloaded.");
+    }
+
+    this.session = await ai.createTextSession({
+      topK: this.topK,
+      temperature: this.temperature,
+    });
+  }
+
+  /**
+   * Call `.destroy()` to free resources if you no longer need a session.
+   * When a session is destroyed, it can no longer be used, and any ongoing
+   * execution will be aborted. You may want to keep the session around if
+   * you intend to prompt the model often since creating a session can take
+   * some time.
+   */
+  destroy() {
+    if (!this.session) {
+      return console.log("No session found. Returning.");
+    }
+    this.session.destroy();
+  }
+
+  async *_streamResponseChunks(
+    messages: BaseMessage[],
+    _options: this["ParsedCallOptions"],
+    runManager?: CallbackManagerForLLMRun
+  ): AsyncGenerator<ChatGenerationChunk> {
+    if (!this.session) {
+      throw new Error("Session not found. Please call `.initialize()` first.");
+    }
+    const textPrompt = formatPrompt(messages);
+
+    const stream = this.session.promptStreaming(textPrompt);
+    const reader = stream.getReader();
+
+    try {
+      let previousLength = 0;
+      while (true) {
+        const { done, value } = await reader.read();
+        if (done) break;
+        const newContent = value.slice(previousLength);
+        previousLength = value.length;
+        yield new ChatGenerationChunk({
+          text: newContent,
+          message: new AIMessageChunk({
+            content: newContent,
+            additional_kwargs: {},
+          }),
+        });
+        await runManager?.handleLLMNewToken(newContent);
+      }
+    } finally {
+      reader.releaseLock();
+    }
+  }
+
+  async _call(
+    messages: BaseMessage[],
+    options: this["ParsedCallOptions"],
+    runManager?: CallbackManagerForLLMRun
+  ): Promise<string> {
+    const chunks = [];
+    for await (const chunk of this._streamResponseChunks(
+      messages,
+      options,
+      runManager
+    )) {
+      chunks.push(chunk.text);
+    }
+    return chunks.join("");
+  }
+}

libs/langchain-community/src/chat_models/tests/chrome_ai.html

@@ -0,0 +1,34 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <title>ChatChromeAI Example</title>
+  </head>
+  <body>
+    <h1>ChatChromeAI Example</h1>
+
+    <form id="inputForm">
+      <label for="inputField">Enter your input:</label><br />
+      <input type="text" id="inputField" name="inputField" /><br />
+      <button type="submit">Submit</button>
+    </form>
+
+    <script type="module">
+      import { ChatChromeAI } from "../../../dist/chat_models/chrome_ai.js";
+
+      const model = new ChatChromeAI();
+
+      document
+        .getElementById("inputForm")
+        .addEventListener("submit", async (event) => {
+          event.preventDefault();
+
+          const input = document.getElementById("inputField").value;
+          const humanMessage = ["human", input];
+
+          for await (const chunk of await model.stream(humanMessage)) {
+            console.log(chunk);
+          }
+        });
+    </script>
+  </body>
+</html>

libs/langchain-community/src/load/import_map.ts

@@ -46,6 +46,7 @@ export * as vectorstores__vectara from "../vectorstores/vectara.js";
 export * as chat_models__alibaba_tongyi from "../chat_models/alibaba_tongyi.js";
 export * as chat_models__baiduwenxin from "../chat_models/baiduwenxin.js";
 export * as chat_models__cloudflare_workersai from "../chat_models/cloudflare_workersai.js";
+export * as chat_models__chrome_ai from "../chat_models/chrome_ai.js";
 export * as chat_models__deepinfra from "../chat_models/deepinfra.js";
 export * as chat_models__fireworks from "../chat_models/fireworks.js";
 export * as chat_models__friendli from "../chat_models/friendli.js";