# 代码片段

# CORS

app.all("*", function (req, res, next) {
  //设置允许跨域的域名,*代表允许任意域名跨域
  res.header("Access-Control-Allow-Origin", "*");
  //允许的header类型
  res.header("Access-Control-Allow-Headers", "content-type");
  //跨域允许的请求方式
  res.header("Access-Control-Allow-Methods", "DELETE,PUT,POST,GET,OPTIONS");
  // next
  next();
});