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npm1 /
Last active December 14, 2021 08:22
Interaction ID Explainer

Interaction ID

Nicolás Peña Moreno

Hongbo Song


Currently, developers can measure the latency of an event using the Event Timing API. Developers may query the duration, which returns the next paint after event handlers have run. Or they may compute the input delay, the delta between startTime (the event's timeStamp) and processingStart, which is a timestamp taken right before event is dispatched. But measuring event latency separately can’t help developers fully understand the user’s pain. When a user interacts with a web page, a user interaction (i.e. click/tap, press a key, drag) usually triggers a sequence of events. For example, when the user c

alekseykulikov /
Last active August 3, 2021 20:53
Github Actions Ranking (June 18, 2020)

Github Actions is a CI/CD platform that gained a lot of popularity recently. I participated in building ⭐️ Lighthouse CI Action and was curious how well it performs.

But Github Marketplace UI shows no ranking information. Essentially, It's a search with random results; at least, I don't understand the order. I couldn't find ⭐️ Lighthouse CI Action in Continuous integration category after browsing 50 available pages (Each page shows 20 results, so it's possible to see only 1000 results, but CI category has 1469 😐).

I decided to build a custom script that crawls all categories and use Github Search (example query) to estimate usa

input[type="search"]::-webkit-search-cancel-button {
--size: 11px;
--background: #7F7F7F;
--icon: url("data:image/svg+xml;base64,PHN2ZyB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciIHdpZHRoPSI3IiBoZWlnaHQ9IjciIHZpZXdCb3g9IjAgMCAyNCAyNCIgZmlsbD0ibm9uZSIgc3Ryb2tlPSIjZmZmIiBzdHJva2Utd2lkdGg9IjMiIHN0cm9rZS1saW5lY2FwPSJyb3VuZCIgc3Ryb2tlLWxpbmVqb2luPSJyb3VuZCIgY2xhc3M9ImZlYXRoZXIgZmVhdGhlci14Ij48cGF0aCBkPSJNMTggNkw2IDE4TTYgNmwxMiAxMiIvPjwvc3ZnPgo=");
-webkit-appearance: none;
height: var(--size);
width: var(--size);
border-radius: 50%;
background: var(--background) var(--icon) 50% 50% no-repeat;
developit / *
Last active July 25, 2023 12:54
more-or-less instant command-line ESM to CJS transform. Copies from src to dist. `cjyes src/*.js`

cjyes npm version

🔍 see jay, yes! 🎉 / 👨🏻‍💻 see, JS! 👾 / ⚓️ sea JS ⛴

If you're publishing ES Modules, you need to also publish CommonJS versions of those modules.

This isn't to support old browsers or Node versions: even in Node 14, using require() to load a module won't work if it's only available as ESM.

cjyes is the bare minimum fix for this problem. You write ES Modules and fill out a valid package.json, and it'll generate the corresponding CommonJS files pretty much instantly. cjyes takes up 500kb of disk space including its two dependencies.

export const h=(t,p,...c)=>({t,p,c,k:p&&p.key})
export const render=(e,d,t=d.t||(d.t={}),p,r,c,m,y)=>
// arrays,p)=>render(e,d,t.o&&t.o[p])):
// components{children:e.c},e.p),e.s=t.s||{},t=>
// create notes
m=t.d||(e.t?document.createElement(e.t):new Text(e.p)),
// diff props


A tiny ~150-byte polyfill for Promise.prototype.finally.

Useful for browsers that support Promise but not the .finally() method.


npm install finally-polyfill (

(10min demo at the meetup, 20 November 2019, Amsterdam)

CrUX is the Chrome User Experience Report, a public dataset of performance and UX data from real Chrome users in the field.

Quick facts:

  • Launched in November 2017
  • Monthly data dumps (second Tuesday)
alekseykulikov /
Last active July 2, 2023 14:20
Extra features of PageSpeed Insights API

In this article, I would like to share three features of PageSpeed Insights (PSI), that is not easy to find in the official documentation. I discovered them while hacking on the Lighthouse plugin and integrating PSI to

For a context, PSI is a simple yet powerful API by Google, that audits your page using Lighthouse and provides real-world users' data from Chrome UX Report (CrUX).

1. Audit many categories with one request

By default, PSI API returns only performance category. It's possible to pass ?category argument multiple times and get a report with many Lighthouse categories using one request (available categories: performance, accessibility, best-practices, seo, pwa).

curl -i "
ilblog /
Last active June 16, 2024 05:09
Create mp4 video from set of images in the browser client side, using ffmpeg.js in worker thread

Proposal: Importable Constructable Stylesheets

We're getting Constructable Stylesheets. This seems like an intuitive value to obtain when importing CSS from JavaScript, since it's the DOM's representation of a Stylesheet:

import stylesheet from './style.css';
console.log(stylesheet);  // CSSStyleSheet

No such system is in place to allow this to work (see [whatwg/loader]), however frontend build tooling has congregated around this approach as a mechanism for bringing CSS assets into the JavaScript module graph. There are many benefits to be obtained from moving CSS into this graph, however the most important is that imported CSS can be attributed to the consuming JS Module. This allows it to be bundled, optimized, and potentially dead-code-eliminated leveraging static analysis performed on the surrounding module graph.