Add more docs for calling chatopenai with functions (langchain-ai#1646)

examples/src/models/chat/integration_openai.ts

@@ -7,20 +7,19 @@ const model = new ChatOpenAI({
   openAIApiKey: "YOUR-API-KEY", // In Node.js defaults to process.env.OPENAI_API_KEY
 });
 
-// You can also pass functions to the model, learn more here
+// You can also pass tools or functions to the model, learn more here
 // https://platform.openai.com/docs/guides/gpt/function-calling
 
 const modelForFunctionCalling = new ChatOpenAI({
   modelName: "gpt-4-0613",
   temperature: 0,
 });
 
-const result = await modelForFunctionCalling.predictMessages(
+await modelForFunctionCalling.predictMessages(
   [new HumanChatMessage("What is the weather in New York?")],
   { tools: [new SerpAPI()] }
+  // Tools will be automatically formatted as functions in the OpenAI format
 );
-
-console.log(result);
 /*
 AIChatMessage {
   text: '',
@@ -33,3 +32,42 @@ AIChatMessage {
   }
 }
 */
+
+await modelForFunctionCalling.predictMessages(
+  [new HumanChatMessage("What is the weather in New York?")],
+  {
+    functions: [
+      {
+        name: "get_current_weather",
+        description: "Get the current weather in a given location",
+        parameters: {
+          type: "object",
+          properties: {
+            location: {
+              type: "string",
+              description: "The city and state, e.g. San Francisco, CA",
+            },
+            unit: { type: "string", enum: ["celsius", "fahrenheit"] },
+          },
+          required: ["location"],
+        },
+      },
+    ],
+    // You can set the `function_call` arg to force the model to use a function
+    function_call: {
+      name: "get_current_weather",
+    },
+  }
+);
+/*
+AIChatMessage {
+  text: '',
+  name: undefined,
+  additional_kwargs: {
+    function_call: {
+      name: 'get_current_weather',
+      arguments: '{\n  "location": "New York"\n}'
+    }
+  }
+}
+*/