Javascript 未处理的PromisejectionWarning:ReferenceError:运行Puppeter时未定义浏览器？

我刚开始使用木偶演员，我想抓取某个网站的一些数据，但我收到了这些警告，我没有在控制台上显示任何数据

为什么我会收到以下警告，我如何才能消除它们

以下是我使用的代码：

const puppeteer = require("puppeteer");

(async () => {
  // prepare for headless chrome
  const browser = await puppeteer.launch();
  const page = await browser.newPage();

  // set user agent (override the default headless User Agent)
  await page.setUserAgent(
    "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/81.0.4044.129 Safari/537.36"
  );

  // go to website home page
  await page.goto("https://www.nytimes.com/");
  await page.waitForSelector("body");
  // get the User Agent on the context of Puppeteer
  const userAgent = await page.evaluate(() => navigator.userAgent);
  var rposts = await page.evaluate(() => {
    postItems = [];
    let posts = document.body.querySelectorAll(".assetWrapper");
    posts.forEach((item) => {
      try {
        title = item.querySelector("h2").innerText;
        link = item.querySelector("a").href;
        summary = item.querySelector("p").innerText;
        postItems.push({ title: title, link: link, summary: summary });
      } catch (e) {}
    });
    var items = {
      posts: postItems,
    };
    return items;
  });
  // If everything correct then no 'HeadlessChrome' sub string on userAgent
  console.log(userAgent);
  console.log(rposts);
  await browser.close();
})();

以下是我得到的错误： （节点：4072）未处理的PromisejectionWarning:引用错误：未定义浏览器

---

（节点：15452）未经处理的Promisejection警告：引用错误：初始化前无法访问“页面”

创建无头浏览器，然后您可以使用这些代码

    const browser = await puppeteer.launch({
        headless: false
    });

问候,