README.md

For some cases could be useful to exclude some core-js features or generate a polyfill for target engines. This API helps conditionally include or exclude certain parts of core-js and build for targets. modules, exclude and targets options are specified in the core-js-compat format.

import builder from 'core-js-builder';

const bundle = await builder({
  modules: ['core-js/actual', 'esnext.reflect'],     // entries / modules / namespaces, by default - all `core-js` modules
  exclude: [/^es\.math\./, 'es.number.constructor'], // a blacklist of entries / modules / namespaces, by default - empty list
  targets: '> 0.5%, not dead, ie 9-11',              // optional browserslist or core-js-compat format query
  summary: {                                         // shows summary for the bundle, disabled by default:
    console: { size: true, modules: false },         // in the console, you could specify required parts or set `true` for enable all of them
    comment: { size: false, modules: true },         // in the comment in the target file, similarly to `summary.console`
  },
  filename: PATH_TO_MY_COREJS_BUNDLE,                // optional target filename, if it's missed a file will not be created
});