s2s-handler-css-to-flow

Config

s2s.config.js

const handlerCssToFlow = require('s2s-handler-css-to-flow').default

module.exports = {
  watch: './**/*.css',
  plugins: [
    {
      test: /.*.css$/,
      handler: handlerCssToFlow,
      output: '[name].css.flow',
    },
  ],
}

or use DEFAULT_CONFIG

const { DEFAULT_CONFIG } = require('s2s-handler-css-to-flow')

module.exports = {
  watch: './**/*.css',
  plugins: [DEFAULT_CONFIG],
}