Prettier-modify

prettier-modify is a CLI and JS library that allows to define modifier functions that will modify the AST additionally to prettier formatting job.

In order to benefit from prettier-modify, you need to define modifiers in a .prettierrc.js file like the following:

module.exports = {
  modifiers: {
    css: {
      options: { singleQuote: false }, // This will override prettier options or overrides
      mutate: node => {
        if (node.type === 'css-rule') {
          node.nodes = node.nodes
            // This will remove duplicates
            .reduceRight((acc, v) => {
              if (!acc.some(x => x.prop === v.prop)) acc.push(v)
              return acc
            }, [])
            // This will sort properties alphabetically
            .sort((a, b) => (a.prop > b.prop ? 1 : -1))
        }
      },
    },
  },
}

Then you can use it like this:

npm i prettier-modify
prettier-modify input.css

NOTE: prettier-modify was tested on html, css, js, yaml, markdown, vue.

NOTE: Each mutate function is slightly different and depends on prettier's AST parsers. See test/.prettierrc.js file for some advanced examples.

NOTE: prettier-modify is a simple CLI so it won't display prettier's original CLI warnings and only allows file input. On the other hand it boots in 100ms versus 1s for prettier's cli.