js/tests/integration/rollup.bundle.mjs

import { babel } from '@rollup/plugin-babel'
import { nodeResolve } from '@rollup/plugin-node-resolve'
import replace from '@rollup/plugin-replace'

export default {
  input: 'js/tests/integration/bundle.js',
  output: {
    file: 'js/coverage/bundle.js',
    format: 'iife'
  },
  plugins: [
    replace({
      'process.env.NODE_ENV': '"production"',
      preventAssignment: true
    }),
    nodeResolve(),
    babel({
      exclude: 'node_modules/**',
      babelHelpers: 'bundled'
    })
  ]
}