自定义中间件

• middleware/koa-pv.js

const pv = ctx => {
  console.log("path:" + ctx.path);
};

module.exports = () => async (ctx, next) => {
  pv(ctx);
  await next();
};

• app.js

const Koa = require("koa");
const pv = require("./middleware/koa-pv");
app.use(pv());