server-timing

server-timing

This module adds Server-Timing to response headers. Example is here and open chrome devtool network tab.

You can use this as a express module / basic http function.

Install

$ npm install server-timing -S

Usage

const express = require('express');
const serverTiming = require('server-timing');

const app = express();
app.use(serverTiming());

app.use((req, res, next) => {
  res.startTime('file', 'File IO metric');
  setTimeout(() => {
    res.endTime('file');
  }, 100);
  next();
});
app.use((req, res, next) => {
  // you can see test end time response
  res.startTime('test', 'forget to call endTime');
  next();
});
app.use((req, res, next) => {
  // All timings should be in milliseconds (s). See issue #9 (https://github.com/yosuke-furukawa/server-timing/issues/9).
  res.setMetric('db', 100.0, 'Database metric');
  res.setMetric('api', 200.0, 'HTTP/API metric');
  res.setMetric('cache', 300.0, 'cache metric');
  next();
});
app.use((req, res, next) => {
  res.send('hello');
});

Conditionally enabled

const express = require('express');
const serverTiming = require('server-timing');

const app = express();
app.use(serverTiming({
  // Only send metrics if query parameter `debug` is set to `true`
  enabled: (req, res) => req.query.debug === 'true'
}));

API

constructor(options)

• options.name: string, default total, name for the timing item
• options.description: string, default Total Response Time, explanation for the timing item
• options.total: boolean, default true, add total response time
• options.enabled: boolean | function, default true, enable server timing header. If a function is passed, it will be called with two arguments, request and response, and should return a boolean.
• options.autoEnd: boolean, default true automatically endTime is called if timer is not finished.
• options.precision: number, default +Infinity, number of decimals to use for timings.

Result