text: 
  import del from 'del';
  import fs from './lib/fs';
  
  /**
   * Cleans up the output (build) directory.
   */
  export default () => new Promise((resolve, reject) => {
    console.log('clean');
    del(['.tmp', 'build/*', '!build/.git'], {dot: true}, err => {
      if (err) {
        reject(err);
      } else {
        fs.makeDir('build/public').then(resolve, reject);
      }
    });
  });
  