How to send an array of chat messages to Google Gemini API instead of a single message?

import { GoogleGenerativeAI } from "@google/generative-ai";
const genAI = new GoogleGenerativeAI(process.env.GEMINIAPIKEY);
const model = genAI.getGenerativeModel({ model: "gemini-1.5-flash" });
const messages = [
  { role: "user", content: "Hello" },
  { role: "assistant", content: "Hi! How can I help?" },
  { role: "user", content: "Explain AI simply." }
];
const contents = messages.map(msg => ({
  role: msg.role === "assistant" ? "model" : "user",
  parts: [{ text: msg.content }]
}));
const response = await model.generateContent({ contents });
console.log(response.response.text());