Rollup + @babel/preset-env + @babel/polyfill

Question

When using Rollup how can you get it to work with both @babel/preset-env and @babel/polyfill ? The docs mentioned to add useBuiltIns: 'usage' but when I do this I get a require is not defined error in console. Below is what I have so far; is there a more recommended setup?

rollup.config.js:

 import babel from 'rollup-plugin-babel'; import resolve from 'rollup-plugin-node-resolve'; import { terser } from 'rollup-plugin-terser'; const dist = './dist/'; const name = 'focusoverlay'; export default { input: './src/index.js', output: [ { file: `${dist}${name}.cjs.js`, format: 'cjs' }, { file: `${dist}${name}.esm.js`, format: 'esm' }, { name: 'FocusOverlay', file: `${dist}${name}.js`, format: 'umd' } ], plugins: [ resolve(), babel({ exclude: 'node_modules/**' }), terser() ] }; 

.babelrc:

{
  "presets": [
    [
      "@babel/preset-env",
      {
        "useBuiltIns": "usage",
        "modules": false,
        "targets": {
          "browsers": "> 0.25%, not op_mini all, not dead, IE 10-11",
          "node": 6
        }
      }
    ]
  ]
}

Answer 1

I fixed this by removing my .babelrc file and moving my babel configuration entirely to rollup.config.js . Then I also included the rollup-plugin-commonjs plugin to convert CJS modules to ES6. Example of my final config:

import babel from 'rollup-plugin-babel';
import resolve from 'rollup-plugin-node-resolve';
import commonjs from 'rollup-plugin-commonjs';
import { terser } from 'rollup-plugin-terser';

const dist = './dist/';
const name = 'focusoverlay';

export default {
  input: './src/index.js',
  output: [
    {
      file: `${dist}${name}.cjs.js`,
      format: 'cjs'
    },
    {
      file: `${dist}${name}.esm.js`,
      format: 'esm'
    },
    {
      name: 'FocusOverlay',
      file: `${dist}${name}.js`,
      format: 'umd'
    }
  ],
  plugins: [
      resolve(),
      babel({
        exclude: 'node_modules/**',
        presets: [
          [
            '@babel/env',
            {
              modules: 'false',
              targets: {
                browsers: '> 1%, IE 11, not op_mini all, not dead',
                node: 8
              },
              useBuiltIns: 'usage'
            }
          ]
        ]
      }),
      commonjs(),
      terser()
  ]
};

Full config here . Suggestions for improvement of course still welcome.