2020-11-02 koa计算响应时间中间件

async function responseTime(ctx, next) {
  const start = new Date();
  await next();
  const ms = new Date() - start;
  ctx.set("X-Response-Time", ms + "ms");
}

async function respond(ctx, next) {
  await next();
  if ("/" != ctx.url) return;
  ctx.body = "Hello World";
}

加上log4js可统计每个资源和请求的耗时