SyntaxError: Invalid or unexpected token

[zhangwei900808]

next.config.js

const withCss = require("@zeit/next-css");
const withSass = require("@zeit/next-sass");
const withPlugins = require("next-compose-plugins");
/* eslint-disable */
const withLess = require("@zeit/next-less");
const lessToJS = require("less-vars-to-js");
const fs = require("fs");
const path = require("path");
const withImages = require("next-images");

// Where your antd-custom.less file lives
const themeVariables = lessToJS(fs.readFileSync(path.resolve(__dirname, "./src/assets/styles/antd-custom.less"), "utf8"));

module.exports = withPlugins([withCss, withLess, withSass, withImages], {
  cssLoaderOptions: {
    importLoaders: 1
  },
  lessLoaderOptions: {
    javascriptEnabled: true,
    modifyVars: themeVariables // make your antd custom effective
  },
  webpack: (config, { isServer }) => {
    if (isServer) {
      const antStyles = /antd\/.*?\/style.*?/;
      const hiynnStyles = /hiynn-design\/.*?\/style.*?/;
      const origExternals = [...config.externals];
      config.externals = [
        (context, request, callback) => {
          if (request.match(antStyles) || request.match(hiynnStyles)) {
            return callback();
          }
          if (typeof origExternals[0] === "function") {
            origExternals[0](context, request, callback);
          } else {
            callback();
          }
        },
        ...(typeof origExternals[0] === "function" ? [] : origExternals)
      ];
      config.module.rules.push(
        {
          test: antStyles,
          use: "null-loader"
        },
        {
          test: hiynnStyles,
          use: "null-loader"
        }
      );
    }
    return config;
  }
});

when I run next build