javascript - UnhandledPromiseRejectionWarning:TypeError:未定义不是函数

我一直在尝试按照以下教程操作此刮板
https://www.youtube.com/watch?v=TzZ3YOUhCxo

我曾尝试刮刮亚马逊以防黄页无法正常工作。我从节点12转到节点13。我尝试使用完整的xpath。如果保存时的格式导致错误，请禁用更漂亮。

帮助我不明白为什么此代码无法正常工作。我向上帝发誓，我要逐行从youtube复制。

(node:1740) UnhandledPromiseRejectionWarning: TypeError: undefined is not a function
    at scrapeProduct (C:\Users\hello\coding\scrapy\server.js:8:16)
    at processTicksAndRejections (internal/process/task_queues.js:97:5)
(node:1740) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). To terminate the node process on unhandled promise rejection, use the CLI flag `--unhandled-rejections=strict` (see https://nodejs.org/api/cli.html#cli_unhandled_rejections_mode). (rejection id: 1)
(node:1740) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.

const puppeteer = require("puppeteer");

async function scrapeProduct(url) {
  const browser = await puppeteer.launch();
  const page = await browser.newPage();
  await page.goto(url);

  const [el] = page.$x('/html/body/div[2]/div/div[1]/div[1]/div[2]/div[2]/div[1]/div/div/div[2]/h2/a/span');
  const src = await el.getProperty("src");
  const srcTxt = await src.jsonValue();

  console.log({srcTxt});
}

scrapeProduct('https://www.yellowpages.com/search?search_terms=cpa&geo_location_terms=New%20York%2C%20NY&page=1');

最佳答案

每当在一个等待中被拒绝的承诺被拒绝时，总是在async/await中使用try / catch，它将抛出一个错误，应该由catch来捕获。

const puppeteer = require("puppeteer");

async function scrapeProduct(url) {
    try {
        const browser = await puppeteer.launch();
        const page = await browser.newPage();
        await page.goto(url);

        const [el] = page.$x('/html/body/div[2]/div/div[1]/div[1]/div[2]/div[2]/div[1]/div/div/div[2]/h2/a/span');
        const src = await el.getProperty("src");
        const srcTxt = await src.jsonValue();


        console.log({ srcTxt });
    } catch (e) {
        console.log(e, "ERROR");
    }
}

scrapeProduct('https://www.yellowpages.com/search?search_terms=cpa&geo_location_terms=New%20York%2C%20NY&page=1');

在您的环境中运行上面的代码，您将了解导致问题的原因。

关于javascript - UnhandledPromiseRejectionWarning:TypeError:未定义不是函数，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/60333432/