rollup.config.js

import lwc from '@lwc/rollup-plugin';
import copy from 'rollup-plugin-copy';
import serve from 'rollup-plugin-serve';
import replace from '@rollup/plugin-replace';
import { nodeResolve as resolveSubdirectoryImports } from '@rollup/plugin-node-resolve';
import { terser } from 'rollup-plugin-terser';
import livereload from 'rollup-plugin-livereload';


const production = (process.env.NODE_ENV === 'production');
const watching = Boolean(process.env.ROLLUP_WATCH);

export default {
    input: 'src/index.js',
    output: {
        sourcemap: watching,
        dir: 'dist',
        format: 'esm',
    },
    watch: {
        clearScreen: false,
        include: 'src/**'
    },
    plugins: [
        resolveSubdirectoryImports(),
        lwc({ sourcemap: watching }),
        replace({ "process.env.NODE_ENV": JSON.stringify(process.env.NODE_ENV) }),
        copy({
            targets: [
                { src: 'src/index.html', dest: 'dist' },
                { src: 'src/assets', dest: 'dist' },
            ]
        }),
        production && terser(),
        watching && serve('dist'),
        watching && livereload({ watch: 'dist', delay: 400 })
    ].filter(Boolean)
};