Arjan Audit

Arjan audit is a simple node module that helps automate the auditing process of static sites during the dev process using Google’s lighthouse 6. Often times when building a site, the page speed test is one of the last things we do. To avoid any surprise surprise, you can use arjan audit in your dev process or even integrate it into your tests.

How it works

Arjan audit uses express to serve your site and google chrome-launcher to make a headless launch of google chrome and retrieve the audits from lighthouse 6. Arjan then parses the results returned by lighthouse and return an organized subset of the results. When used from the CLI, arjan returns a neatly formatted report.

Getting Started

1. install the arjan CLI globally. npm i -g arjan-cli
2. inside your proejct direcotry, initialize arja arjan init
3. run an audit arjan audit

CLI Command

USAGE
  $ arjan audit

OPTIONS
  -d, --dir=dir              Directory path to serve. default is root (relative to the path in which you run the command)

  -f, --file=file            Path of the page you want to audit. default is index.html

  -p, --port=port            Port used for the test server. Default is 8080.

  -t, --threshold=threshold  Integer value from 0 to 1 that represents what you consider to be an acceptable lighthouse score for your site. Its very similar to what you would consider an acceptable school test grade.

Programmatic use example

const Audit = require('arjan-audit')
Audit('./', 'index.html', 8080, .7)
.then(data=> console.log(data))
.catch(err=>console.log(err))

API

main

description: params: (dir, index, port, threshhold)

 **dir**: string
 **index**: string
 **port**: int
**treshhold**: float: number between 0 and 1

returns: Promise(resolve, reject)

**resolve**: string: formatted
**reject**: error

The Audit Report

the audit report is a subset of data from the JSON response of lighthouse 6. for more information on the parameters of lighthouse 6 see this link

{
  "lh5_score":float,
  "lh6_score":float,
  "main_metrics":{
    "metric":{
      "title":"string",
      "score":float,
      "description":"string"
    }
  },
  "improvements":{
    "improvement":{
      "title":"title",
      "score":float,
      "description":"description",
      "details":{}
    }
  }
}

Lighthouse 6 score

Google recently recalculated the score of what they consdier a healthy fast site. The new LCP metric was introduced and the score weights and metrics were changed. for more information check out Google’s Web Vitals

Audit	Weight
First Contentful Paint	15%
Speed Index	15%
Largest Contentful Paint	25%
Time to Interactive	15%
Total Blocking Time	25%
Cumulative Layout Shift	5%

For more info read the docs