docs: function globFile (file) {
      return stat(file).then(({ err, stats }) => {
        if (err) throw err
        if (stats.isDirectory()) {
          // TODO what if file is already slash-terminated?
          switch (file) {
            case './':
              return globPromise('./*.js')
            case 'bin':
              return globPromise('bin/*')
            default:
              return globPromise(`${file}/**/*.js`)
          }
        } else {
          return Promise.resolve(file)
        }
      })
    }