可以在plugin加入參數即可，v4跟v2版本有很大的差異。

在此提供兩種版本的方式。

Webpack v4

// 需引入uglifyjs-webpack-plugin,這邊與v2就不一樣
const UglifyJsPlugin = require('uglifyjs-webpack-plugin');
plugins: [
    new UglifyJsPlugin({
        sourceMap: true,
        uglifyOptions: {
            ie8: false,
            ecma: 8,
            parse: {},
            mangle: true,
            output: {
                comments: false,
                beautify: false
            },
            compress: true,
            warnings: false
            }
    })
]

Webpack v2

// v2 版本直接使用webpack.optimize即可
plugins: [
    new webpack.optimize.UglifyJsPlugin({
        sourceMap: true,
        compress: {
            warnings: false, // remove 警告
            drop_console: true // 移除console.log
        }
    })
]

Reference

https://blog.csdn.net/xiaoguang44/article/details/89555376

https://blog.csdn.net/xiasohuai/article/details/88527483

https://segmentfault.com/a/1190000015032321