rollup.config.ssr.js

import svelte from 'rollup-plugin-svelte'
import resolve from '@rollup/plugin-node-resolve'
import pkg from './package.json'

const name = pkg.name
	.replace(/^(@\S+\/)?(svelte-)?(\S+)/, '$3')
	.replace(/^\w/, m => m.toUpperCase())
	.replace(/-\w/g, m => m[1].toUpperCase())

export default {
	input: 'src/index.js',
	output: [
		{ file: pkg.module, 'format': 'es' },
		{ file: pkg.main, 'format': 'umd', name }
	],
	plugins: [
		svelte({
			

				// By default, the client-side compiler is used. You
				// can also use the server-side rendering compiler
				generate: 'ssr',
		
				// ensure that extra attributes are added to head
				// elements for hydration (used with generate: 'ssr')
				hydratable: true,
		
				// Emit CSS as "files" for other plugins to process
				emitCss: false,

				// You can optionally set 'customElement' to 'true' to compile
				// your components to custom elements (aka web elements)
				customElement: false,
				// Extract CSS into a single bundled file (recommended).
				// See note below
				css: function (css) {
					css.write('button.css', false)
				},

				//svelte: require('svelte')
			}
		),
		resolve()
	]
}