メニュー
Expert guidance for HTML/XML parsing using Cheerio in Node.js with best practices for DOM traversal, data extraction, and efficient scraping pipelines.
Codex または Claude でインストール この Prompt をコピーして Codex、Claude、または他のアシスタントに貼り付けると、Skill ページを確認してインストールできます。
SOC 職業分類に基づく
Implement web accessibility (a11y) best practices following WCAG guidelines to create inclusive, accessible user interfaces.
Alpine.js development guidelines for lightweight reactive interactions with Tailwind CSS and various backend frameworks.
Implement analytics, data analysis, and visualization best practices using Python, Jupyter, and modern data tools.
Android development guidelines for Kotlin with clean architecture, MVI pattern, Material Design, and best practices for building robust mobile applications
Expert guidance for Angular and TypeScript development focused on scalable, high-performance web applications
Expert in Angular TypeScript development with scalable, high-performance patterns
| name | cheerio-parsing |
| description | Expert guidance for HTML/XML parsing using Cheerio in Node.js with best practices for DOM traversal, data extraction, and efficient scraping pipelines. |
You are an expert in Cheerio, Node.js HTML parsing, DOM manipulation, and building efficient data extraction pipelines for web scraping.
npm install cheerio axios
const cheerio = require('cheerio');
const axios = require('axios');
// Load from string
const $ = cheerio.load('<html><body><h1>Hello</h1></body></html>');
// Load with options
const $ = cheerio.load(html, {
xmlMode: false, // Parse as XML
decodeEntities: true, // Decode HTML entities
lowerCaseTags: false, // Keep tag case
lowerCaseAttributeNames: false
});
// Fetch and parse
async function fetchAndParse(url) {
const response = await axios.get(url);
return cheerio.load(response.data);
}
// By tag
$('h1')
// By class
$('.article')
// By ID
$('#main-content')
// By attribute
$('[data-id="123"]')
$('a[href^="https://"]') // Starts with
$('a[href$=".pdf"]') // Ends with
$('a[href*="example"]') // Contains
// Combinations
$('div.article > h2') // Direct child
$('div.article h2') // Any descendant
$('h2 + p') // Adjacent sibling
$('h2 ~ p') // General sibling
// Pseudo-selectors
$('li:first-child')
$('li:last-child')
$('li:nth-child(2)')
$('li:nth-child(odd)')
$('tr:even')
$('input:not([type="hidden"])')
$('p:contains("specific text")')
// Select multiple types
$('h1, h2, h3')
// Chain selections
$('.article').find('.title')
// Get text (includes child text)
const text = $('h1').text();
// Get trimmed text
const text = $('h1').text().trim();
// Get HTML
const html = $('div.content').html();
// Get outer HTML
const outerHtml = $.html($('div.content'));
// Get attribute
const href = $('a').attr('href');
const src = $('img').attr('src');
// Get data attributes
const id = $('div').data('id'); // data-id attribute
// Check if attribute exists
const hasClass = $('div').hasClass('active');
// Iterate with each
const items = [];
$('.product').each((index, element) => {
items.push({
name: $(element).find('.name').text().trim(),
price: $(element).find('.price').text().trim(),
url: $(element).find('a').attr('href')
});
});
// Map to array
const titles = $('h2').map((i, el) => $(el).text()).get();
// Filter elements
const featured = $('.product').filter('.featured');
// First/Last
const first = $('li').first();
const last = $('li').last();
// Get by index
const third = $('li').eq(2);
// Parent
$('span').parent()
$('span').parents() // All ancestors
$('span').parents('.container') // Specific ancestor
$('span').closest('.wrapper') // Nearest ancestor matching selector
// Children
$('ul').children() // Direct children
$('ul').children('li.active') // Filtered children
$('div').contents() // Including text nodes
// Siblings
$('li').siblings()
$('li').next()
$('li').nextAll()
$('li').prev()
$('li').prevAll()
// Filter by selector
$('li').filter('.active')
// Filter by function
$('li').filter((i, el) => $(el).data('price') > 100)
// Find within selection
$('.article').find('img')
// Check conditions
$('li').is('.active') // Returns boolean
$('li').has('span') // Has descendant matching selector
function extractTable(tableSelector) {
const $ = this;
const headers = [];
const rows = [];
// Get headers
$(tableSelector).find('th').each((i, el) => {
headers.push($(el).text().trim());
});
// Get rows
$(tableSelector).find('tbody tr').each((i, row) => {
const rowData = {};
$(row).find('td').each((j, cell) => {
rowData[headers[j]] = $(cell).text().trim();
});
rows.push(rowData);
});
return rows;
}
function extractList(selector, itemExtractor) {
return $(selector).map((i, el) => itemExtractor($(el))).get();
}
// Usage
const products = extractList('.product', ($el) => ({
name: $el.find('.name').text().trim(),
price: parseFloat($el.find('.price').text().replace('$', '')),
image: $el.find('img').attr('src'),
link: $el.find('a').attr('href')
}));
function extractPaginationLinks() {
return $('.pagination a')
.map((i, el) => $(el).attr('href'))
.get()
.filter(href => href && !href.includes('#'));
}
// Safe extraction with defaults
function safeText(selector, defaultValue = '') {
const el = $(selector);
return el.length ? el.text().trim() : defaultValue;
}
function safeAttr(selector, attr, defaultValue = null) {
const el = $(selector);
return el.length ? el.attr(attr) : defaultValue;
}
// Optional chaining pattern
const price = $('.price').first().text()?.trim() || 'N/A';
const { URL } = require('url');
function resolveUrl(baseUrl, relativeUrl) {
if (!relativeUrl) return null;
try {
return new URL(relativeUrl, baseUrl).href;
} catch {
return relativeUrl;
}
}
// Usage
const baseUrl = 'https://example.com/products/';
$('a').each((i, el) => {
const href = $(el).attr('href');
const absoluteUrl = resolveUrl(baseUrl, href);
console.log(absoluteUrl);
});
// Cache selections
const $products = $('.product');
$products.each((i, el) => {
const $product = $(el); // Wrap once
// Use $product multiple times
});
// Limit parsing scope
const $article = $('.article');
const title = $article.find('.title').text(); // Searches only within article
// Use specific selectors
// Good
$('div.product > h2.title')
// Less efficient
$('div').find('.product').find('h2').filter('.title')
const cheerio = require('cheerio');
const axios = require('axios');
async function scrapeProducts(url) {
const response = await axios.get(url, {
headers: {
'User-Agent': 'Mozilla/5.0 (compatible; MyScraper/1.0)'
}
});
const $ = cheerio.load(response.data);
const products = [];
$('.product-card').each((index, element) => {
const $el = $(element);
products.push({
name: $el.find('.product-title').text().trim(),
price: parseFloat(
$el.find('.price').text().replace(/[^0-9.]/g, '')
),
rating: parseFloat($el.find('.rating').attr('data-rating')) || null,
image: $el.find('img').attr('src'),
url: new URL($el.find('a').attr('href'), url).href,
inStock: !$el.find('.out-of-stock').length
});
});
return products;
}
// With error handling
async function safeScrape(url) {
try {
return await scrapeProducts(url);
} catch (error) {
console.error(`Failed to scrape ${url}:`, error.message);
return [];
}
}