升级vue-loader依赖包后造成require()方法返回是

vue-loader在13.x以后通过require导入的包默认esModule是true；造成直接通过require方法引入的静态资源无法使用；需要手动添加default属性；
解决方法就是重置vue-loader中的url-loader配置；解决步骤如下：

1. 安装url-loader

npm i url-loader

2. 更改vue.config.js,替换规则里的loader参考替换规则里的loader；在链式操作里重新配置url-loader；配置如下；

  chainWebpack (config) {
    config.plugins.delete("preload"); // TODO: need test
    config.plugins.delete("prefetch"); // TODO: need test
    // reset url-loader
    const urlRule = config.module.rule('images')
    // 清除已有的所有 loader。
    // 如果你不这样做，接下来的 loader 会附加在该规则现有的 loader 之后。
    urlRule.uses.clear()
    // 添加要替换的 loader
    urlRule
      .use("url-loader")
      .loader("url-loader")
      .options({
        limit: 8192,
        esModule: false
      })
    // set svg-sprite-loader
    config.module
      .rule("svg")
      .exclude.add(resolve("src/icons"))
      .end();
    config.module
      .rule("icons")
      .test(/\.svg$/)
      .include.add(resolve("src/icons"))
      .end()
      .use("svg-sprite-loader")
      .loader("svg-sprite-loader")
      .options({
        symbolId: "icon-[name]"
      })
      .end();

    // set preserveWhitespace
    config.module
      .rule("vue")
      .use("vue-loader")
      .loader("vue-loader")
      .tap(options => {
        options.compilerOptions.preserveWhitespace = true;
        return options;
      })
      .end();

    config
      // https://webpack.js.org/configuration/devtool/#development
      .when(process.env.NODE_ENV === "development", config =>
        config.devtool("cheap-source-map")
      );

    config.when(process.env.NODE_ENV !== "development", config => {
      config
        .plugin("ScriptExtHtmlWebpackPlugin")
        .after("html")
        .use("script-ext-html-webpack-plugin", [
          {
            // `runtime` must same as runtimeChunk name. default is `runtime`
            inline: /runtime\..*\.js$/
          }
        ])
        .end();
      config.optimization.splitChunks({
        chunks: "all",
        cacheGroups: {
          libs: {
            name: "chunk-libs",
            test: /[\\/]node_modules[\\/]/,
            priority: 10,
            chunks: "initial" // only package third parties that are initially dependent
          },
          elementUI: {
            name: "chunk-elementUI", // split elementUI into a single package
            priority: 20, // the weight needs to be larger than libs and app or it will be packaged into libs or app
            test: /[\\/]node_modules[\\/]_?element-ui(.*)/ // in order to adapt to cnpm
          },
          commons: {
            name: "chunk-commons",
            test: resolve("src/components"), // can customize your rules
            minChunks: 3, //  minimum common number
            priority: 5,
            reuseExistingChunk: true
          }
        }
      });
      config.optimization.runtimeChunk("single");
     
    });
  }

配置完成后重新
npm run dev
思路参考