As Encore is a builder for the webpack config, you can easily alter the final config before exporting it:

// webpack.config.js

var Encore = require('@symfony/webpack-encore');

// all Encore config here

var config = Encore.getWebpackConfig();

config.watchOptions = { poll: true, ignored: /node_modules/ };

module.exports = config;

We should doc this as the official approach of adding "extra" config. I don't think there's any benefit of adding another method on Encore to set things like this. I've opened and issue: symfony/symfony-docs#8067

Thanks!

Thank you
Is a good news