node.js - Cheerio 有时会返回 undefined

Question

你是否曾经使用cheerio 来解析html。有时如果太快它会不确定？

我检查了返回未定义的页面。获取数据没有问题。因为我有条件检查来自cheerio的解析是否未定义。它将返回cheerio 解析的html。它存在。但是cheerio parse有时会返回未定义。如果我再次重复，有时它会返回未定义的解析？究竟是什么问题？

import fetch from 'node-fetch';
import { load } from 'cheerio';

(async () => {
    const options = {
        headers: {
            "user-agent": "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/71.0.3578.80 Safari/537.36"
        }
    };

    const response = await fetch('https://hentairead.com/page/1/', options);
    const $ = load(await response.text());

    const totalPage = $('span.pages')
                        .text()
                        .match(/\d{3,}/g)
                        .toString();

    for(let page = 1; page <= totalPage; page++)
    {
        const response = await fetch(`https://hentairead.com/page/${page}/`, options);
        const $ = load(await response.text());

        $('div.item-thumb.c-image-hover > a').each(async (index, item) => {
            const title = item.attribs.title;
            const url = item.attribs.href;

            const response = await fetch(`${url}english/`, options);
            const html = await response.text();

            const $ = load(html);

            const totalPage = $('select#single-pager > option:last-child').attr('value');

            if(totalPage !== undefined){
                console.log(title);
                console.log(totalPage);
            }else{
                console.log(html);
            }
        });
    }
})();

标签： node.jscheerio