function filterFiles (filters) {
  return (files, metalsmith, done) => {
    filter(files, filters, metalsmith.metadata(), done)
  }
}
function filterFiles (filters) {
  return (files, metalsmith, done) => {
    filter(files, filters, metalsmith.metadata(), done)
  }
}
function filterFiles ( filters ) { return ( files , metalsmith , done ) => { filter ( files , filters , metalsmith . metadata ( ) , done ) } }
Create a middleware for filtering files.

@param {Object} filters
@return {Function}
Create a middleware for filtering files .
filter files by filter