Error: clean-webpack-plugin only accepts an options object. See: https://github.com/johnagan/clean-webpack-plugin#options-and-defaults-optional

webpack中文文档中推荐这样使用，but 执行npm run build 

Error: clean-webpack-plugin only accepts an options object. See:
https://github.com/johnagan/clean-webpack-plugin#options-and-defaults-optional

解决方法：

new CleanWebpackPlugin() 去掉参数就可以了