现在有一个专门的 状态功能在响应对象上。

  res.status （404）// HTTP status 404：NotFound 
 .send（'Not found'）; 
 

I want to simulate a 404 error on my Express/Node server. How can I do that?

Nowadays there's a dedicated status function for this on the response object. Just chain it in somewhere before you call send.

res.status(404)        // HTTP status 404: NotFound
   .send('Not found');