https://github.com/Alfred-Skyblue/vue-draggable-plus/issues/189

webpack打包开启代码压缩，且项目中使用vue-draggable-plus并开启reduce_vars时，运行时报错。
需关闭reduce_vars。

module.exports = {
  ...
  // 优化配置
  optimization: {
   ...
    minimizer: [
      new TerserPlugin({
        terserOptions: {
          compress: {
            ...
            reduce_vars: false,
          },
          ...