根据主题，我试图在htmlstring中的元素上使用cheerio循环并提取href属性。
在以下示例中，.each永远不会运行。
const cheerio = require('cheerio');
const htmlparser2 = require('htmlparser2');
var htmlstring = '<!DOCTYPE html><html xmlns="http://www.w3.org/1999/xhtml" lang="da" ng-app="sdk.portal"><head><meta charset="utf-8"><meta http-equiv="X-UA-Compatible" content="IE=edge"><meta name="viewport" content="width=device-width, initial-scale=1, minimum-scale=1, maximum-scale=1, user-scalable=0"><meta sdk-core-metatags-directive><title data-ng-bind="metaTagVm.titleTag"></title><link rel="stylesheet" type="text/css" href="/public/css/sdk-06a073b7f6.styleguide.css"><link rel="stylesheet" type="text/css" href="/public/css/sdk-2f8a814242.styleguide-blessed1.css"><link rel="apple-touch-icon" sizes="180x180" href="../../public/images/apple-touch-icon.png"><link rel="icon" type="image/png" href="../../public/images/favicon-32x32.png" sizes="32x32"><link rel="icon" type="image/png" href="../../public/images/favicon-16x16.png" sizes="16x16"><link rel="manifest" href="/manifest.json"><link rel="mask-icon" href="../../public/images/safari-pinned-tab.svg" color="#b20c1c"><meta name="msapplication-TileColor" content="#b20c1c"><meta name="msapplication-TileImage" content="../../public/images/mstile-144x144.png"><meta name="theme-color" content="#ffffff"><script src="/public/js/vendor-f84d227302.js"></script><script src="/public/js/sdk-a8dae725ad.bundle.js"></script><base href="/" /><sdk-core-analytics></sdk-core-analytics></head><body><div><div ui-view="coreView"><div style="width: 30%; margin-left: auto; margin-right: auto; text-align: center"><!--[if lt IE 9]><h2>Opdatér din browser for at bruge sundhed.dk</h2><p>Det ser ud til, at du bruger et browser-program af ældre dato.<br/>Sundhed.dk’s mange funktioner kræver nu en nyere browser.</p><p/>Download en opdateret browser her: <hr/><a href="https://www.microsoft.com/da-dk/download/details.aspx?id=29254">Internet Explorer</a><hr/><a href="https://www.google.com/chrome/browser/desktop/index.html">Chrome</a><hr/><a href="https://www.mozilla.org/da/firefox/new/">Firefox</a><hr/><a href="http://www.opera.com/da/download">Opera</a></p><![endif]--><!--[if (gte IE 9) | (!IE)]><p>Vent et øjeblik</p><![endif]--></div></div></div><div id="includes"><div id="includePlaceholder"></div></div></body></html>';
var dom = htmlparser2.parseDOM(htmlstring);
var $ = cheerio.load(dom);
$('a').each(function(idx, el) {
console.log('in each');
var $el = $(el);
var att = $el.attr('href');
console.log(att);
});
如果我试着看看$（＆＃39; a＆＃39;）给了我什么，那就是以下对象：
initialize {
options:
{ withDomLvl1: true,
normalizeWhitespace: false,
xml: false,
decodeEntities: true },
_root:
initialize {
'0':
{ type: 'root',
name: 'root',
namespace: 'http://www.w3.org/1999/xhtml',
attribs: {},
'x-attribsNamespace': {},
'x-attribsPrefix': {},
children: [Object],
parent: null,
prev: null,
next: null },
options:
{ withDomLvl1: true,
normalizeWhitespace: false,
xml: false,
decodeEntities: true },
length: 1,
_root: [Circular] },
length: 0,
prevObject:
initialize {
'0':
{ type: 'root',
name: 'root',
namespace: 'http://www.w3.org/1999/xhtml',
attribs: {},
'x-attribsNamespace': {},
'x-attribsPrefix': {},
children: [Object],
parent: null,
prev: null,
next: null },
options:
{ withDomLvl1: true,
normalizeWhitespace: false,
xml: false,
decodeEntities: true },
length: 1,
_root: [Circular] } }
这看起来像是cheerio选项对象，所以我做错了什么，实际上它是一个我怀疑的cheerio的错误，因为它看起来好像我按照我的方式做事情期待。
答案 0 :(得分：0)
我在cheeriojs https://github.com/cheeriojs/cheerio/issues/1063上询问了这个问题，有人指出所有链接都在条件评论中，所以我的代码应该是
const cheerio = require('cheerio');
const htmlparser2 = require('htmlparser2');
var htmlstring = '<html lang="da"><head><meta charset="utf-8"><meta http-equiv="X-UA-Compatible" content="IE=edge"><meta name="viewport" content="width=device-width, initial-scale=1, minimum-scale=1, maximum-scale=1, user-scalable=0"><meta sdk-core-metatags-directive><title data-ng-bind="metaTagVm.titleTag"></title><link rel="stylesheet" type="text/css" href="/public/css/sdk-06a073b7f6.styleguide.css"><link rel="stylesheet" type="text/css" href="/public/css/sdk-2f8a814242.styleguide-blessed1.css"><link rel="apple-touch-icon" sizes="180x180" href="../../public/images/apple-touch-icon.png"><link rel="icon" type="image/png" href="../../public/images/favicon-32x32.png" sizes="32x32"><link rel="icon" type="image/png" href="../../public/images/favicon-16x16.png" sizes="16x16"><link rel="manifest" href="/manifest.json"><link rel="mask-icon" href="../../public/images/safari-pinned-tab.svg" color="#b20c1c"><meta name="msapplication-TileColor" content="#b20c1c"><meta name="msapplication-TileImage" content="../../public/images/mstile-144x144.png"><meta name="theme-color" content="#ffffff"><script src="/public/js/vendor-f84d227302.js"></script><script src="/public/js/sdk-a8dae725ad.bundle.js"></script><base href="/" /><sdk-core-analytics></sdk-core-analytics></head><body><div><div ui-view="coreView"><div style="width: 30%; margin-left: auto; margin-right: auto; text-align: center"><h2>Opdatér din browser for at bruge sundhed.dk</h2><p>Det ser ud til, at du bruger et browser-program af ældre dato.<br/>Sundhed.dk’s mange funktioner kræver nu en nyere browser.</p><p/>Download en opdateret browser her: <hr/><a href="https://www.microsoft.com/da-dk/download/details.aspx?id=29254">Internet Explorer</a><hr/><a href="https://www.google.com/chrome/browser/desktop/index.html">Chrome</a><hr/><a href="https://www.mozilla.org/da/firefox/new/">Firefox</a><hr/><a href="http://www.opera.com/da/download">Opera</a></p><!--[if (gte IE 9) | (!IE)]><p>Vent et øjeblik</p><![endif]--></div></div></div><div id="includes"><div id="includePlaceholder"></div></div></body></html>';
var dom = htmlparser2.parseDOM(htmlstring);
var $ = cheerio.load(dom);
$('a').each(function(idx, el) {
console.log('in each');
var $el = $(el);
var att = $el.attr('href');
console.log(att);
});