How does Cheerio load HTML content? What are the different loading methods?

Cheerio provides multiple methods for loading HTML content, suitable for different use cases:

1. Loading from HTML String

The most common method, directly passing an HTML string:

javascript
const cheerio = require('cheerio');
const $ = cheerio.load('<div class="content"><p>Hello</p></div>');

2. Loading from File

Read HTML file and then load:

javascript
const fs = require('fs');
const cheerio = require('cheerio');

const html = fs.readFileSync('index.html', 'utf8');
const $ = cheerio.load(html);

3. Loading with Configuration Options

The cheerio.load() method accepts a second parameter as configuration options:

javascript
const $ = cheerio.load(html, {
  // Whether to recognize XML mode
  xmlMode: false,
  
  // Whether to decode HTML entities
  decodeEntities: true,
  
  // Whether to include whitespace nodes
  withDomLvl1: false,
  
  // Default function to handle XML tags
  normalizeWhitespace: false,
  
  // Use htmlparser2 options
  xml: {
    xmlMode: false,
    decodeEntities: true
  }
});

4. XML Mode Loading

Enable XML mode when processing XML documents:

javascript
const xml = '<root><item>Value</item></root>';
const $ = cheerio.load(xml, { xmlMode: true });

5. Stream Processing (Combined with other libraries)

For large files, use stream reading:

javascript
const fs = require('fs');
const cheerio = require('cheerio');

const stream = fs.createReadStream('large.html');
let html = '';

stream.on('data', chunk => {
  html += chunk;
});

stream.on('end', () => {
  const $ = cheerio.load(html);
  // Process DOM
});

Best Practices

• For small to medium-sized HTML, use cheerio.load() directly
• For large files, consider chunked processing or use specialized streaming parsers
• For XML documents, always set xmlMode: true
• Adjust decodeEntities option based on requirements