code: async function (directory, filesInSassTree, exclusions) {
    const filesInDirectory = (await recursive(directory));
  
    const unusedFiles = filesInDirectory
      .filter((file) => isUnused(file, filesInSassTree, exclusions));
  
    return unusedFiles;
  }
docs: Compare directory contents with a list of files that are in use
  @param { String } directory
  @param { Array } filesInSassTree
  @param { Array } exclusions
  @returns { Array } files that are unused