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

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.

---

Chaser324

Whether you're trying to give back to the open source community or collaborating on your own projects, knowing how to properly fork and generate pull requests is essential. Unfortunately, it's quite easy to make mistakes or not know what you should do when you're initially learning the process. I know that I certainly had considerable initial trouble with it, and I found a lot of the information on GitHub and around the internet to be rather piecemeal and incomplete - part of the process described here, another there, common hangups in a different place, and so on.

In an attempt to coallate this information for myself and others, this short tutorial is what I've found to be fairly standard procedure for creating a fork, doing your work, issuing a pull request, and merging that pull request back into the original project.

Creating a Fork

Just head over to the GitHub page and click the "Fork" button. It's just that simple. Once you've done that, you can use your favorite git client to clone your repo or j

sebmarkbage

The Rules of React

All libraries have subtle rules that you have to follow for them to work well. Often these are implied and undocumented rules that you have to learn as you go. This is an attempt to document the rules of React renders. Ideally a type system could enforce it.

What Functions Are "Pure"?

A number of methods in React are assumed to be "pure".

On classes that's the constructor, getDerivedStateFromProps, shouldComponentUpdate and render.

bvaughn

This API was removed in React 17

---

Interaction tracing with React

React recently introduced an experimental profiler API. After discussing this API with several teams at Facebook, one common piece of feedback was that the performance information would be more useful if it could be associated with the events that caused the application to render (e.g. button click, XHR response). Tracing these events (or "interactions") would enable more powerful tooling to be built around the timing information, capable of answering questions like "What caused this really slow commit?" or "How long does it typically take for this interaction to update the DOM?".

With version 16.4.3, React added experimental support for this tracing by way of a new NPM package, scheduler. However the public API for this package is not yet finalized and will likely change with upcoming minor releases, so it should be used with caution.

dominictarr

Hey everyone - this is not just a one off thing, there are likely to be many other modules in your dependency trees that are now a burden to their authors. I didn't create this code for altruistic motivations, I created it for fun. I was learning, and learning is fun. I gave it away because it was easy to do so, and because sharing helps learning too. I think most of the small modules on npm were created for reasons like this. However, that was a long time ago. I've since moved on from this module and moved on from that thing too and in the process of moving on from that as well. I've written way better modules than this, the internet just hasn't fully caught up.

@broros

otherwise why would he hand over a popular package to a stranger?

If it's not fun anymore, you get literally nothing from maintaining a popular package.

One time, I was working as a dishwasher in a restu

mcansh

Things to note to make this work:

1. you'll need to have your remix registry token available in your shell under REMIX_TOKEN
2. you'll need to add secrets to your GitHub repo for the following items:
   • REMIX_TOKEN
   • VERCEL_TOKEN (https://vercel.com/account/tokens)
   • VERCEL_ORG_ID
   • VERCEL_PROJECT_ID
3. you'll need to have your REMIX_TOKEN available in your vercel repo as an environment variable

eps1lon

// jonschlinkert/is-object
type IsObjectObject<T> = T extends
  | AnyArray
  | AnyFunction
  | boolean
  | null
  | number
  | string
  | symbol
  | undefined

sebmarkbage

I heard some points of criticism to how React deals with reactivity and it's focus on "purity". It's interesting because there are really two approaches evolving. There's a mutable + change tracking approach and there's an immutability + referential equality testing approach. It's difficult to mix and match them when you build new features on top. So that's why React has been pushing a bit harder on immutability lately to be able to build on top of it. Both have various tradeoffs but others are doing good research in other areas, so we've decided to focus on this direction and see where it leads us.

I did want to address a few points that I didn't see get enough consideration around the tradeoffs. So here's a small brain dump.

"Compiled output results in smaller apps" - E.g. Svelte apps start smaller but the compiler output is 3-4x larger per component than the equivalent VDOM approach. This is mostly due to the code that is usually shared in the VDOM "VM" needs to be inlined into each component. The tr

karlhorky

[alias]
  fetch-pr  = "!f() { git fetch origin refs/pull/$1/head:pr/$1; } ; f"
  delete-prs = "!git for-each-ref refs/heads/pr/* --format='%(refname)' | while read ref ; do branch=${ref#refs/heads/} ; git branch -D $branch ; done"