ryanflorence

function Expletives({ children }) {
  let [, forceUpdate] = useState();
  let mounted = useRef(false);

  useEffect(() => {
    mounted.current = true;

    // don't want to cause any seizures.
    if (window.matchMedia("(prefers-reduced-motion: reduce)").matches) {
      return;

ry

Build-A-Cell

https://www.nature.com/articles/d41586-018-07289-x

https://www.preposterousuniverse.com/podcast/2019/07/22/56-kate-adamala-on-creating-synthetic-life/

http://buildacell.io/

http://buildacell.io/engineering/

swyxio

// create context with no upfront defaultValue
// without having to do undefined check all the time
function createCtx<A>() {
  const ctx = React.createContext<A | undefined>(undefined)
  function useCtx() {
    const c = React.useContext(ctx)
    if (!c) throw new Error("useCtx must be inside a Provider with a value")
    return c
  }
  return [useCtx, ctx.Provider] as const

astoilkov

Async Operations with useReducer Hook

9 March, 2019

We were discussing with @erusev what we can do with async operation when using useReducer() in our application. Our app is simple and we don't want to use a state management library. All our requirements are satisfied with using one root useReducer(). The problem we are facing and don't know how to solve is async operations.

In a discussion with Dan Abramov he recommends Solution 3 but points out that things are fresh with hooks and there could be better ways of handling the problem.

Problem

skbr1234

# Author: Zameer Ansari
# You should look at the following URL's in order to grasp a solid understanding
# of Nginx configuration files in order to fully unleash the power of Nginx.
# http://wiki.nginx.org/Pitfalls
# http://wiki.nginx.org/QuickStart
# http://wiki.nginx.org/Configuration
#
# Generally, you will want to move this file somewhere, and start with a clean
# file but keep this around for reference. Or just disable in sites-enabled.
#

Rich-Harris

Stuff I wish I'd known sooner about service workers

I recently had several days of extremely frustrating experiences with service workers. Here are a few things I've since learned which would have made my life much easier but which isn't particularly obvious from most of the blog posts and videos I've seen.

I'll add to this list over time – suggested additions welcome in the comments or via twitter.com/rich_harris.

Use Canary for development instead of Chrome stable

Chrome 51 has some pretty wild behaviour related to console.log in service workers. Canary doesn't, and it has a load of really good service worker related stuff in devtools.

paulirish

What forces layout / reflow

All of the below properties or methods, when requested/called in JavaScript, will trigger the browser to synchronously calculate the style and layout*. This is also called reflow or layout thrashing, and is common performance bottleneck.

Generally, all APIs that synchronously provide layout metrics will trigger forced reflow / layout. Read on for additional cases and details.

Element APIs

Getting box metrics

• elem.offsetLeft, elem.offsetTop, elem.offsetWidth, elem.offsetHeight, elem.offsetParent

KdotJPG

/**
 * K.jpg's OpenSimplex 2, smooth variant ("SuperSimplex")
 *
 * More language ports, as well as legacy 2014 OpenSimplex, can be found here:
 * https://github.com/KdotJPG/OpenSimplex2
 */

public class OpenSimplex2S {

    private static final long PRIME_X = 0x5205402B9270C86FL;

staltz

The introduction to Reactive Programming you've been missing

(by @andrestaltz)

---

This tutorial as a series of videos

If you prefer to watch video tutorials with live-coding, then check out this series I recorded with the same contents as in this article: Egghead.io - Introduction to Reactive Programming.

---