Whether to analyze dependencies (e.g. @import and url()).
When enabled, @import rules are removed, and url() dependencies
are replaced with hashed placeholders that can be replaced with the final
urls later (after bundling). Dependencies are returned as part of the result.
Replaces user action pseudo classes with class names that can be applied from JavaScript.
This is useful for polyfills, for example.
optional
unusedSymbols: string[]
A list of class names, ids, and custom identifiers (e.g. @keyframes) that are known
to be unused. These will be removed during minification. Note that these are not
selectors but individual names (without any . or # prefixes).