core-js/stable global polyfills mutate native built-ins after import
Adding core-js to a bundle should provide polyfills without changing how existing native methods behave for code that does not opt in. When core-js/stable is used with Babel preset-env, third-party libraries that feature-test built-ins may see modified globals such as Promise or Array. The exact behavior depends on whether core-js/stable or core-js/pure is i
corejs