Babel build warning

[mmarton]

Hi!

I'v got the following warning during build. I'm not sure it's encore related or i just missed some config.
@symfony/webpack-encore@0.25.0
@babel/preset-env@7.4.2

Running webpack ...


WARNING: We noticed you're using the `useBuiltIns` option without declaring a core-js version. Currently, we assume version 2.x when no version is passed. Since this default version will likely change in future versions of Babel, we recommend explicitly setting the core-js version you are using via the `corejs` option.

You should also be sure that the version you pass to the `corejs` option matches the version specified in your `package.json`'s `dependencies` section. If it doesn't, you need to run one of the following commands:

  npm install --save core-js@2    npm install --save core-js@3
  yarn add core-js@2              yarn add core-js@3

Could you help me?
Thanks

[Kocal]

See #545 :)

[mmarton]

I've missed that, thanks

[Lyrkan]

Note that if you don't use polyfills (ie. if you don't import core-js or @babel/polyfill anywhere with the default Babel' settings), you can remove this warning by calling:

Encore.configureBabel(() => {}, {
  useBuiltIns: false
});

If you do use them, you should be fine as long as you explictely have core-js@2 in your dependencies.