rollup.config.js

import resolve from 'rollup-plugin-node-resolve';
import commonjs from 'rollup-plugin-commonjs';
import babel from 'rollup-plugin-babel';

export default {
    format: 'cjs',
    plugins: [
        resolve(),
        commonjs(),
        babel({
            exclude: 'node_modules/**'
        }),
    ],
};