const path = require("path");
const UglifyPlugin = require("uglifyjs-webpack-plugin");
module.exports = {
  // 基本路径
  /* 部署生产环境和开发环境下的URL：可对当前环境进行区分，baseUrl 从 Vue CLI 3.3 起已弃用，要使用publicPath */
  /* baseUrl: process.env.NODE_ENV === 'production' ? './' : '/' */
  publicPath: process.env.NODE_ENV === "production" ? "./" : "./",
  // 输出文件目录
  outputDir: "dist",
  // eslint-loader 是否在保存的时候检查
  lintOnSave: true,
  // use the full build with in-browser compiler?
  // https://vuejs.org/v2/guide/installation.html#Runtime-Compiler-vs-Runtime-only
  //   compiler: false,
  runtimeCompiler: true, //关键点在这
  // 调整内部的 webpack 配置。
  // 查阅 https://github.com/vuejs/vue-doc-zh-cn/vue-cli/webpack.md
  // webpack配置
  // see https://github.com/vuejs/vue-cli/blob/dev/docs/webpack.md
  chainWebpack: () => {},
  configureWebpack: config => {
    if (process.env.NODE_ENV === "production") {
      // 为生产环境修改配置...
      config.mode = "production";
      // 将每个依赖包打包成单独的js文件
      var optimization = {
        runtimeChunk: "single",
        splitChunks: {
          chunks: "all",
          maxInitialRequests: Infinity,
          minSize: 20000, // 依赖包超过20000bit将被单独打包
          cacheGroups: {
            vendor: {
              test: /[\\/]node_modules[\\/]/,
              name(module) {
                // get the name. E.g. node_modules/packageName/not/this/part.js
                // or node_modules/packageName
                const packageName = module.context.match(
                  /[\\/]node_modules[\\/](.*?)([\\/]|$)/
                )[1];
                // npm package names are URL-safe, but some servers don't like @ symbols
                return `npm.${packageName.replace("@", "")}`;
              }
            }
          }
        },
        minimizer: [
          new UglifyPlugin({
            uglifyOptions: {
              compress: {
                warnings: false,
                drop_console: true, // console
                drop_debugger: false,
                pure_funcs: ["console.log"] // 移除console
              }
            }
          })
        ]
      };
      Object.assign(config, {
        optimization
      });
    } else {
      // 为开发环境修改配置...
      config.mode = "development";
      var optimization2 = {
        runtimeChunk: "single",
        splitChunks: {
          chunks: "all",
          maxInitialRequests: Infinity,
          minSize: 20000, // 依赖包超过20000bit将被单独打包
          cacheGroups: {
            vendor: {
              test: /[\\/]node_modules[\\/]/,
              name(module) {
                // get the name. E.g. node_modules/packageName/not/this/part.js
                // or node_modules/packageName
                const packageName = module.context.match(
                  /[\\/]node_modules[\\/](.*?)([\\/]|$)/
                )[1];
                // npm package names are URL-safe, but some servers don't like @ symbols
                return `npm.${packageName.replace("@", "")}`;
              }
            }
          }
        }
      };
    }
    Object.assign(config, {
      // 开发生产共同配置

      // externals: {
      //   'vue': 'Vue',
      //   'element-ui': 'ELEMENT',
      //   'vue-router': 'VueRouter',
      //   'vuex': 'Vuex'
      // } // 防止将某些 import 的包(package)打包到 bundle 中，而是在运行时(runtime)再去从外部获取这些扩展依赖(用于csdn引入)
      resolve: {
        extensions: [".js", ".vue", ".json"], //文件优先解析后缀名顺序
        alias: {
          "@": path.resolve(__dirname, "./src"),
          "@c": path.resolve(__dirname, "./src/components"),
          "@v": path.resolve(__dirname, "./src/views"),
          "@u": path.resolve(__dirname, "./src/utils"),
          "@s": path.resolve(__dirname, "./src/service")
        }, // 别名配置
        plugins: []
      },
      optimization: optimization2
    });
  },
  // vue-loader 配置项
  // https://vue-loader.vuejs.org/en/options.html
  // vueLoader: {},
  // 生产环境是否生成 sourceMap 文件
  productionSourceMap: false,
  // css相关配置
  css: {
    // 是否使用css分离插件 ExtractTextPlugin
    // extract: true, //注释css热更新生效
    // 开启 CSS source maps?
    sourceMap: false,
    // css预设器配置项
    loaderOptions: {},
    // 启用 CSS modules for all css / pre-processor files.
    modules: false
  },
  // use thread-loader for babel & TS in production build
  // enabled by default if the machine has more than 1 cores
  parallel: require("os").cpus().length > 1,
  // 是否启用dll
  // See https://github.com/vuejs/vue-cli/blob/dev/docs/cli-service.md#dll-mode
  // dll: false,
  // PWA 插件相关配置
  // see https://github.com/vuejs/vue-cli/tree/dev/packages/%40vue/cli-plugin-pwa
  pwa: {},
  // webpack-dev-server 相关配置
  devServer: {
    /* 自动打开浏览器 */
    open: false,
    // host: "192.168.0.137",
    host: "0.0.0.0", //局域网和本地访问
    //host: "192.168.1.137",
    port: 8080,
    https: false,
    hotOnly: false,
    /* 使用代理 */
    proxy: {
      "/api": {
        /* 目标代理服务器地址 */
        // target: "http://192.168.0.106:8080/",
        target: "http://192.168.1.126:8080/", //阳洋
        /* 允许跨域 */
        changeOrigin: true,
        ws: true,
        pathRewrite: {
          "^/api": ""
        }
      }
    },
    before: () => {}
  },
  // 第三方插件配置
  pluginOptions: {}
};

简易版：

const path = require("path");
const resolve = function(dir) {
  return path.join(__dirname, dir);
};
module.exports = {
  publicPath: process.env.NODE_ENV === "production" ? "./" : "./",
  outputDir: "dist",
  assetsDir: "static",
  lintOnSave: true, // 是否开启eslint保存检测
  productionSourceMap: false, // 是否在构建生产包时生成sourcdeMap
  chainWebpack: config => {
    config.resolve.alias
      .set("@", resolve("src"))
      .set("@v", resolve("src/views"))
      .set("@c", resolve("src/components"))
      .set("@u", resolve("src/utils"))
      .set("@s", resolve("src/service")); /* 别名配置 */
    config.optimization.runtimeChunk("single");
  },
  devServer: {
    // host: "localhost",
    /* 本地ip地址 */
    //host: "192.168.1.107",
    host: "0.0.0.0", //局域网和本地访问
    port: "8080",
    hot: true,
    /* 自动打开浏览器 */
    open: false,
    overlay: {
      warning: false,
      error: true
    },
    /* 跨域代理 */
    proxy: {
      "/api": {
        /* 目标代理服务器地址 */
        target: "http://m260048y71.zicp.vip", //
        // target: "http://192.168.1.102:8888", //
        /* 允许跨域 */
        changeOrigin: true,
        ws: true,
        pathRewrite: {
          "^/api": ""
        }
      }
    }
  }
};