Leon Sorokin leeoniya

How to think about Monads

UPDATE 2021: I wrote this long before I wrote my book Functional Programming Made Easier: A Step-by-step Guide. For a much more in depth discussion on Monads see Chapter 18.

Initially, Monads are the biggest, scariest thing about Functional Programming and especially Haskell. I've used monads for quite some time now, but I didn't have a very good model for what they really are. I read Philip Wadler's paper Monads for functional programming and I still didnt quite see the pattern.

It wasn't until I read the blog post You Could Have Invented Monads! (And Maybe You Already Have.) that I started to see things more clearly.

This is a distillation of those works and most likely an oversimplification in an attempt to make things easier to understand. Nuance can come later. What we need when first le

Demo: Coordinating async React with non-React views

tl;dr I built a demo illustrating what it might look like to add async rendering to Facebook's commenting interface, while ensuring it appears on the screen simultaneous to the server-rendered story.

A key benefit of async rendering is that large updates don't block the main thread; instead, the work is spread out and performed during idle periods using cooperative scheduling.

But once you make something async, you introduce the possibility that things may appear on the screen at separate times. Especially when you're dealing with multiple UI frameworks, as is often the case at Facebook.

How do we solve this with React?

A non-exhaustive list of WebGL and WebGPU frameworks and libraries. It is mostly for learning purposes as some of the libraries listed are wip/outdated/not maintained anymore.

Engines and libraries ⚙️

Name	Stars	Last Commit	Description
three.js	![GitH

How to setup Let's Encrypt for Nginx on Ubuntu 18.04 (including IPv6, HTTP/2 and A+ SLL rating)

Virtual hosts

Let's say you want to host domains first.com and second.com.

Create folders for their files:

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

	(function (context, trackingId, options) {
	const history = context.history;
	const doc = document;
	const nav = navigator \|\| {};
	const storage = localStorage;
	const encode = encodeURIComponent;
	const pushState = history.pushState;
	const typeException = 'exception';
	const generateId = () => Math.random().toString(36);
	const getId = () => {

	#!/bin/bash

	# This assumes that the ~6GB mojave installer is in the /Applications folder.
	# If it's not, just open the App Store, search Mojave, and you can download the installer file from there.

	hdiutil create -o /tmp/mojave.cdr -size 6g -layout SPUD -fs HFS+J
	hdiutil attach /tmp/mojave.cdr.dmg -noverify -mountpoint /Volumes/install_mojave
	sudo /Applications/Install\ macOS\ mojave.app/Contents/Resources/createinstallmedia --volume /Volumes/install_mojave
	mv /tmp/mojave.cdr.dmg ~/Desktop/InstallSystem.dmg
	hdiutil detach /Volumes/Install\ macOS\ mojave

	import { createCipheriv, createDecipheriv, randomBytes } from "crypto";

	const ENCRYPTION_KEY: string = process.env.ENCRYPTION_KEY \|\| ""; // Must be 256 bits (32 characters)
	const IV_LENGTH: number = 16; // For AES, this is always 16

	/**
	* Will generate valid encryption keys for use
	* Not used in the code below, but generate one and store it in ENV for your own purposes
	*/
	export function keyGen() {

	////////////////////////////////////////////////////////////////////////////
	//
	// Node.js HTTP file server example.
	//
	// Serves documents via GET requests with CORS headers and (if enabled)
	// additionally permits writes via POST requests.
	//
	// Before using, PLEASE be aware of the security risks associated with
	// running a server like this on publicly accessible machines!
	//

	function processBodyChunkwiseWithProgress(res, processChunk) {
	const dummyEventTarget = document.createElement("div"); // why isn't EventTarget constructible? :(

	const lengthComputable = res.headers.has("Content-Length");
	const total = res.headers.get("Content-Length") \|\| 0;
	let loaded = 0;

	// Using http://underscorejs.org/#throttle
	const fireProgressThrottled = _.throttle(fireProgress, 50, { trailing: false });