rollup.config.mjs

import { babel } from '@rollup/plugin-babel';
import { nodeResolve } from '@rollup/plugin-node-resolve';
import terser from '@rollup/plugin-terser';
import typescript from '@rollup/plugin-typescript';
import peerDepsExternal from 'rollup-plugin-peer-deps-external';

const INPUT_DIR = './src/';
const OUTPUT_DIR = './dist/';

const IS_PRODUCTION = process.env.NODE_ENV === 'production';

const getPlugins = (declarationDir, minification = false) =>
    [
        typescript({
            compilerOptions: {
                rootDir: INPUT_DIR,
                declaration: true,
                declarationDir: `${declarationDir}`,
            },
        }),
        babel({ babelHelpers: 'bundled' }),
        nodeResolve(),
        peerDepsExternal(),
        minification && terser(),
    ].filter(Boolean);

const getOutput = () => ({
    exports: 'named',
    sourcemap: true,
    preserveModules: true,
    entryFileNames: (chunkInfo) => `${chunkInfo.name.replace('src/', '')}.js`,
});

const getModule = (format) => ({
    input: `${INPUT_DIR}index.ts`,
    plugins: getPlugins(`${OUTPUT_DIR}${format}/`, IS_PRODUCTION),
    output: {
        ...getOutput(),
        format: format,
        dir: `${OUTPUT_DIR}${format}`,
    },
});

export default [getModule('es'), getModule('cjs')];