【跨域问题】Access-Control-Allow-Origin 轻松解决

今天学习ajax的时候遇到了跨域问题

’‘Access to XMLHttpRequest at ‘http://localhost:3000/framework/create’ from origin ‘http://localhost:4200’ has been blocked by CORS policy: Response to preflight request doesn’t pass access control check: No ‘Access-Control-Allow-Origin’ header is present on the requested resource.’'

搜了很多地方发现都不能处理,后来在b站的一个视频找到了解决办法

https://www.bilibili.com/video/BV1gt411S78C

首先需要装一个包.

打开编辑器终端.
输入npm i cors , 回车
然后输入app.use(require('cors')());

像这样
如此简单,只需这一行代码就轻松解决跨域问题了