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DropCSS takes your HTML and CSS as input and returns only the used CSS as output. Its custom HTML and CSS parsers are highly optimized for the 99% use case and thus avoid the overhead of handling malformed markup or stylesheets, so well-formed input is required. There is minimal handling for complex escaping rules, so there will always exist cases of valid input that cannot be processed by DropCSS; for these infrequent cases, please start a discussion. While the HTML spec allows html, head, body and tbody to be implied/omitted, DropCSS makes no such assumptions; selectors will only be retained for tags that can be parsed from provided markup. It's also a good idea to run your CSS through a structural optimizer like clean-CSS, csso, cssnano or crass to re-group selectors, merge redundant rules, etc. It probably makes sense to do this after DropCSS, which can leave redundant blocks.
Features
- An exceptionally fast, thorough and tiny (~10 KB min) unused-CSS cleaner (MIT Licensed)
- It's also a good idea to run your CSS through a structural optimizer
- Return false to retain the selector or true to drop it
- Retention of all transient pseudo-class and pseudo-element selectors which cannot be deterministically checked from the parsed HTML
- Deep resolution of composite CSS variables
- Removal of unused CSS variables
Project Samples
