index.js

// move to main.js
define(['utils/array', 'react'], function (array, React) {
  React.render();
});

// move to index.js
const rollup = require('rollup');
const amd = require('rollup-plugin-amd');
const fs = require('fs');

const writeES6Module = ({ modules: [module] }) => fs.writeFile('main.amd.js', module.code, function (err) {
  if (err) return console.log(err);
});

rollup.rollup({
  entry: 'main.js',
  plugins: [
    amd()
  ]
}).then(writeES6Module);

// then run "node index"