web-speed-compare

NodeJS app that runs lighthouse against multiple websites and reports the comparison. This was built with the purpose of assessing the impact of 3rd party scripts on a website, by measuring the website's performance blocking scripts one by one.

How to use

• Install it as a global package: npm i -g web-speed-compare.
• Create a json config file based on the example-config.json file.
• Run the tool: web-speed-compare --config-file=config.json.

Arguments

• --config-file (required): path to the configuration json file.
• --output (optional): by default the tool will print the report in a nice table. You can specify ``--output=md` to print the result in a markdown table.

Configuration file

Example:

{
    "chromeFlags": ["--no-sandbox", "--headless", "--incognito"],
    "runs": 5,
    "pages": [
        {
            "url": "https://github.com/",
            "name": "Github",
            "blockedPatterns": []
        },
        {
            "url": "https://github.com/",
            "name": "Github w/o spotify image",
            "blockedPatterns": ["*spotify*"]
        }
    ]
}

• chromeFlags: array of flags that will be passed to the Chrome launcher.
• runs: number of times the tool will run Lighthouse on each page. The results will show the median of each metric. With a higher number the metrics will be more accurate, but the tool will take longer to run. Defaults to 3.
• pages: array of objects with the information of pages to run the tool against.
  • url: url of the page
  • name: name to be used in the report
  • blockedPatterns: array of strings with patterns of the assets that will be blocked by Chrome. You can use this to block 3rd party scripts and measure the website's performance without them.

Example

web-speed-compare --config-file=config.json --output=md

| Metric                  | Google | Google w/o JS | Google w/o icons |
| :---------------------- | :----: | :-----------: | :--------------: |
| Performance Score       |   96   |      100      |        96        |
| First Contentful Paint  |  1245  |      1269     |       1268       |
| First Meaningful Paint  |  1260  |      1272     |       1294       |
| Speed Index             |  1602  |      1480     |       1656       |
| Estimated Input Latency |   42   |       12      |        45        |
| Total Blocking Time     |   312  |       0       |        340       |
| Max Potential FID       |   238  |       48      |        230       |
| Time To First Byte      |   97   |       98      |        92        |
| First CPU Idle          |  3426  |      1272     |       3411       |
| Time to Iteractive      |  3662  |      1272     |       3647       |
| NetworkRequests         |   29   |       10      |        30        |
| Total Byte Weight       | 308711 |     83967     |      305444      |
| DOM Size                |   411  |      388      |        411       |