Error: webpack.optimize.UglifyJsPlugin has been removed, please use config.optimizat

var webpack=require(‘webpack‘);
var HtmlwebpackPlugin=require(‘html-webpack-plugin‘);
var ExtractTextPlugin=require(‘extract-text-webpack-plugin‘);
var merge=require(‘webpack-merge‘);
var webpackBaseConfig=require(‘./webpack.config.js‘);

// 清空基本配置的插件列表
webpackBaseConfig.plugins=[];

module.exports=merge(webpackBaseConfig,{
    output:{
        publicPath:‘/dist/‘,
        // 将入口文件重命名为带有20位hash值得唯一文件
        filename:‘[name].[hash].js‘
    },
    plugins:[
        new ExtractTextPlugin({
            // 提取CSS，并重命名为带有20为hash值得唯一文件
            filename:‘[name].[hash].css‘,
            allChunks:true
        }),
        // 定义当前node环境为生产环境
        new webpack.DefinePlugin({
            ‘process.env‘:{
                NODE_ENV:‘"production"‘
            }
        }),
        // 压缩js
            new webpack.optimize.UglifyJsPlugin({
                compress:{
                    warnings:false
                }
            }),
        // 提取模板，并保存入口html文件
        new HtmlwebpackPlugin({
            filename:‘../index_prod.html‘,
            template:‘./index.ejs‘,
            inject:false
        })
    ]
});

......
const UglifyJsPlugin=require(‘uglifyjs-webpack-plugin‘);

// 清空基本配置的插件列表
webpackBaseConfig.plugins=[];

module.exports=merge(webpackBaseConfig,{
    output:{
        publicPath:‘/dist/‘,
        // 将入口文件重命名为带有20位hash值得唯一文件
        filename:‘[name].[hash].js‘
    },
    plugins:[
        ......
    ],
    optimization:{
        minimizer:[
            new UglifyJsPlugin({
                uglifyOptions: {
                    output: {
                        comments: false
                    },
                    compress: {
                        warnings: false,
                        drop_debugger: true,
                        drop_console: true
                    }
                }
            })
        ]
    }
});