Cheerio is a fast, flexible, and elegant library for parsing and manipulating HTML and XML on the server side (Node.js). It provides a jQuery-like API for traversing and manipulating the DOM of parsed documents, designed for web scraping, data extraction, and HTML transformation tasks. The library abstracts away the underlying parser (htmlparser2 for speed, parse5 for standards compliance) via a factory pattern, offering a consistent Cheerio API regardless of parser choice. Key entry points include the main `load` function that converts HTML strings or buffers into a Cheerio instance, static methods like `html`, `xml`, `text`, and `parseHTML`, and utility functions for CSS handling, form serialization, and attribute manipulation. External dependencies include cheerio-select for CSS selector parsing, domutils for core DOM traversal, and optional HTTP fetching via undici for live URL parsing.
htmlparser2 is a fast, forgiving HTML/XML parser for Node.js and browsers, written in TypeScript. It provides a low-level streaming tokenizer (Tokenizer) that feeds events to a higher-level Parser, which handles tag matching, implicit closing, foreign content (SVG/MathML), and entity decoding. The library also includes Node.js WritableStream and Web Streams API WritableStream adapters for piping data directly into the parser. It is the foundation for cheerio and other DOM manipulation libraries. The codebase is well-structured, thoroughly tested, and actively maintained, with a focus on performance and spec compliance for real-world HTML.