code: function buildUmdDev() {
    return rollup.rollup({
      entry: 'src/index.js',
      plugins: [
        babel(babelOptions)
      ]
    }).then(function (bundle) {
      bundle.generate({
        format: 'umd',
        banner: banner,
        name: 'rc-datetime-picker'
      }).then(({ code }) => {
        return write('dist/rc-datetime-picker.js', code);
      });
    });
  }
docs: Standalone development build