Compatibility

1. Install the dependency used to provide the necessary runtime helpers

yarn add -D @babel/runtime-corejs3
yarn add core-js

OR

npm i --save-dev @babel/runtime-corejs3
npm i --save core-js

2. Upgrade .browserslistrc

defaults
ie 8 # add it

3. Config babel.config.js

module.exports = function (api) {
  let envOptions = api.env('production')
    ? {
        useBuiltIns: 'entry',
        corejs: { version: '3' }
      }
    : {};
  let runtimeOptions = api.env('production') ? { corejs: 3 } : {};

  return {
    presets: [['@babel/preset-env', envOptions]],
    plugins: [['@babel/plugin-transform-runtime', runtimeOptions]]
  };
};

presets options: add modules: 'commonjs' for outdated IE

4. Config balm.config.js

module.exports = {
  scripts: {
    ie8: true
  }
};

5. Upgrade entry js file

• main.js

import './polyfill';

// Your code

• polyfill.js

import 'core-js/stable';
import 'regenerator-runtime/runtime';