rollup.config.js

import resolve from 'rollup-plugin-node-resolve';
import json from '@rollup/plugin-json';
import replace from '@rollup/plugin-replace';
import commonjs from 'rollup-plugin-commonjs';
import svelte from 'rollup-plugin-svelte';
import babel from 'rollup-plugin-babel';
import { terser } from 'rollup-plugin-terser';
import config from 'sapper/config/rollup.js';
import pkg from './package.json';

const mode = process.env.NODE_ENV;
const dev = mode === 'development';
const legacy = !!process.env.SAPPER_LEGACY_BUILD;

const onwarn = (warning, onwarn) => (warning.code === 'CIRCULAR_DEPENDENCY' && /[/\\]@sapper[/\\]/.test(warning.message)) || onwarn(warning);
const dedupe = importee => importee === 'svelte' || importee.startsWith('svelte/');

export default {
	client: {
		input: config.client.input(),
		output: config.client.output(),
//        moduleContext: (id) => {
//            const thisAsWindowForModules = [
//                'node_modules/intl-messageformat/lib/core.js',
//                'node_modules/intl-messageformat/lib/compiler.js',
//                'node_modules/intl-messageformat/lib/formatters.js',
//                'node_modules/intl-format-cache/lib/index.js',
//                'node_modules/intl-messageformat-parser/lib/normalize.js',
//                'node_modules/intl-messageformat-parser/lib/parser.js',
//                'node_modules/intl-messageformat-parser/lib/skeleton.js,',
//                'node_modules/intl-messageformat-parser/lib/skeleton.js',
//            ];
//
//            if (thisAsWindowForModules.some(id_ => id.trimRight().endsWith(id_))) {
//                return 'window';
//            }
//        },
		plugins: [
			replace({
				'process.browser': true,
				'process.env.NODE_ENV': JSON.stringify(mode)
			}),
			svelte({
				dev,
				hydratable: true,
				emitCss: true
			}),
			resolve({
				browser: true,
				dedupe
			}),
			commonjs(),
            
            json({
                    namedExports: false,
                    compact:!dev
            }),

			legacy && babel({
				extensions: ['.js', '.mjs', '.html', '.svelte'],
				runtimeHelpers: true,
				exclude: ['node_modules/@babel/**'],
				presets: [
					['@babel/preset-env', {
						targets: '> 0.25%, not dead'
					}]
				],
				plugins: [
					'@babel/plugin-syntax-dynamic-import',
					['@babel/plugin-transform-runtime', {
						useESModules: true
					}]
				]
			}),

			!dev && terser({
				module: true
			})
		],

		onwarn: function (warning) {
            // Suppress this error message... there are hundreds of them. Angular team says to ignore it.
            // https://github.com/rollup/rollup/wiki/Troubleshooting#this-is-undefined
            if (warning.code === 'THIS_IS_UNDEFINED') {
                return;
            }
            console.error(warning.message);
        },
	},

	server: {
		input: config.server.input(),
		output: config.server.output(),
		plugins: [
			replace({
				'process.browser': false,
				'process.env.NODE_ENV': JSON.stringify(mode)
			}),
			svelte({
				generate: 'ssr',
				dev
			}),
			resolve({
				dedupe
//                browser: true
			}),
			commonjs(),
            json({
                    namedExports: false,
                    compact:!dev
            })
		],
		external: Object.keys(pkg.dependencies).concat(
			require('module').builtinModules || Object.keys(process.binding('natives'))
		),

		onwarn: function (warning) {
            // Suppress this error message... there are hundreds of them. Angular team says to ignore it.
            // https://github.com/rollup/rollup/wiki/Troubleshooting#this-is-undefined
            if (warning.code === 'THIS_IS_UNDEFINED') {
                return;
            }
            console.error(warning.message);
        },
	},

	serviceworker: {
		input: config.serviceworker.input(),
		output: config.serviceworker.output(),
		plugins: [
			resolve(),
			replace({
				'process.browser': true,
				'process.env.NODE_ENV': JSON.stringify(mode)
			}),
			commonjs(),
			!dev && terser()
		],

		onwarn,
	}
};