ascii only for webpack minify config

webpack.config.js

const UglifyJsPlugin = require('uglifyjs-webpack-plugin');

module.exports = {
  //...
  optimization: {
    minimizer: new UglifyJsPlugin({
      uglifyOptions: {
        output: {
          // true for `ascii_only`
          ascii_only: true
        },
      },
    }),
  },
}