Zach’s ugly mug (his face)

Zach Leatherman

The Lighthouse Scores Will Continue Until Morale Improves

July 20, 2020

Continuing in the great web performance tradition of running Lighthouse on so many things that Lighthouse—in shared traits with quarantined pandemic life—begins to have no meaning and rampant nihilism washes over the developer ecosystem, I have added Lighthouse scores to the Starter Projects list on the Eleventy documentation.

As the Eleventy ecosystem has grown, the list of starter projects available has grown as well. This should help aid new developers if they want to use a Starter Project, as well as highlight developers that have put the extra effort into their project’s performance and accessibility.

Adding Scores to Eleventy Docs #

Just looking back at the last four months, this certainly feels like the accumulation of a bunch of different side projects coming together. Here are the different projects at work:

Step 1: Add the URLs #

First I manually compiled a list of starter project demo URLs to Speedlify, a site I built for automated Lighthouse testing and reporting. This was very straightforward based on the work I’ve already completed. You can see the daily updated results of that here:

Step 2: Fetch the Data #

For my personal website, I added Lighthouse scores to the footer using a client-side request to the Speedlify API. That wouldn’t work here—at time of writing there are 18 starter projects. I wouldn’t want 18 requests to the Speedlify API on every page load! So I modified my Eleventy data request to fetch and cache the API data at build time.

The Eleventy documentation already runs every day. Coupled with Speedlify’s daily updates, this means that the scores on the Eleventy documentation will automatically update with new Lighthouse score results every day too. So if a Starter Project author wants to update their project to improve their scores, it requires no manual intervention from me for the scores to update! Jamstack is pretty cool y’all.

Step 3: Render the Data #

Next, I modified the <speedlify-score> web component to render build-time-fetched API data. In markup it looks like this:

<speedlify-score raw-data='{"url":"","timestamp":1595170952102,"ranks":{"hundos":7,"performance":5,"accessibility":6},"lighthouse":{"version":"6.1.1","performance":1,"accessibility":1,"bestPractices":1,"seo":0.97,"total":397},"firstContentfulPaint":815.225,"speedIndex":815.225,"largestContentfulPaint":815.225,"totalBlockingTime":0,"cumulativeLayoutShift":0,"timeToInteractive":815.225,"maxPotentialFirstInputDelay":16,"timeToFirstByte":29.860000000000014,"weight":{"summary":"3 requests • 3 KiB","total":3258,"image":0,"imageCount":0,"script":0,"scriptCount":0,"document":1059,"font":0,"fontCount":0,"stylesheet":2199,"stylesheetCount":2,"thirdParty":0,"thirdPartyCount":0},"axe":{"passes":130,"violations":0}}'></speedlify-score>

It doesn’t seem great to render JSON in a data attribute like that but that’s how it works for now 🙃.

So we’ve eliminated the runtime requests to the Speedlify API—great!

The next logical step is to build-time render the component so that there isn’t any client-side JavaScript used at all 😅. I think that exploration has the potential to yield some very interesting Eleventy/Web Component crossover findings. My initial thought is to use a JavaScript class that you can consume in Node via require or import, in the browser via import or via a web component interface.

The Final Boss #

The final boss-level stage here is to get all of the Built With Eleventy sites onto Speedlify so that anyone can consume the Speedlify API results and put a Lighthouse score widget on their web site. That work is already underway. The logistics of running ~350 sites in Speedlify adds another level of complexity here but it should be achievable. Stay tuned.

Zach’s ugly mug (his face)

Zach is a builder for the web with Netlify. He’s currently fixated on web fonts and static site generators. His public speaking résumé includes talks in eight different countries at events like Beyond Tellerrand, Smashing Conference, CSSConf, and The White House. He is an emeritus of Filament Group, NEJS CONF, and still helps out with NebraskaJS. Read more about Zach »

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I added Lighthouse Scores to my Site’s Footer and You Can Too


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4 Replies
  1. Paul Robert Lloyd

    Paul Robert Lloyd @paulrobertlloyd #

    This is great but… and this is something I’ve been thinking about in relation to my own work as well… frequently running tasks like this on remote infrastructure has an environmental cost. Is it unreasonable to feel increasingly uncomfortable with this trend?

  2. Nicolas Hoizey

    Nicolas Hoizey @nhoizey #

    BTW, what's the update frequency on now? It still says “updated approximately every other Sunday”, but June 8 seems far now… 😅

  3. Zach Leatherman

    Zach Leatherman @zachleat #

    Good question, I haven’t tested PWA yet and I don’t have plans to 🙈 I do know that registering your service worker too early is a performance anti-pattern though!

  4. Jouni Kantola

    Jouni Kantola @jouni_kantola #

    Have you seen any clear signals whether PWAs perform better or worse than sites without manifest and worker?

    1 Mention
    1. Chris Heilmann

      Chris Heilmann @codepo8 #

      The Lighthouse Scores Will Continue Until Morale Improves…