使用中间件获取响应时间

app.js

const koa = require("koa");
const app = new koa();
app.use(async (ctx, next) => {
  let stime = new Date().getTime();
  await next();
  let etime = new Date().getTime();
  ctx.response.type = "text/html";
  ctx.response.body = "<h1>Hello World</h1>";
  console.log(`请求地址：${ctx.path},响应时间：${etime - stime}`);
});

app.use(async (ctx, next) => {
  console.log("中间件 doSomething");
  await next();
  console.log("中间件执行 over");
});

app.listen(3000, () => {
  console.log("server is running at http://localhost:3000");
});