Async Function is crashed.

[brandonxiang]

sveltejs/svelte-loader#62
sveltejs/svelte#717

exclude is essential for babel-loader, because svelte compiler should not be transformed by babel, while runtime needs to be transformed.

{
 rules: [
        {
          // https://github.com/sveltejs/svelte/issues/717
          test: /\.m?js$/,
          exclude: /node_modules\/(?!svelte)/,
          use: 'babel-loader',
        },
        {
          test: /\.svelte$/,
          exclude: /node_modules\/(?!svelte)/,
          use: [
            { loader: 'babel-loader' },
            {
              loader: 'svelte-loader',
              options: {
                emitCss: true,
                hotReload: true,
                preprocess: require('svelte-preprocess')({
                  postcss: true,
                }),
              },
            },
          ],
        },
}