bboy114crew

This script attaches a stopwatch into the toolbar of Leetcode's problem page.

The feature is simple:

• Start/Stop the stopwatch
• Auto start after 2 mins remaining on the problem
• Restore unstopped stopwatch for the next visit on the problem

Use this script with any browser extension allowing attaching JS to the page. (I use User JavaScript and CSS)

bboy114crew

function Pubsub() {
  this.events = {};

}

Pubsub.prototype.publish = function(event, args) {
  if (!this.events[event]) {
    return false;
  }
  var subscribers = this.events[event];

bboy114crew

// This is the object that once its state changes, 
// it will notify all the observers.
function Observable() {
	this.observersList = [];
}
Observable.prototype.addObserver = function(observer) {
	this.observersList.push(observer);
}
Observable.prototype.removeObserver = function (observer) {
	var self = this;

bboy114crew

# The Caddyfile is an easy way to configure your Caddy web server.
#
# Unless the file starts with a global options block, the first
# uncommented line is always the address of your site.
#
# To use your own domain name (with automatic HTTPS), first make
# sure your domain's A/AAAA DNS records are properly pointed to
# this machine's public IP, then replace ":80" below with your
# domain name.

bboy114crew

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.

bboy114crew

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

bboy114crew

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

bboy114crew

// I'm suggesting we add a new "adopt X from <Y />" syntax to the JSX language
// it would de-sugar to render prop children, but look and read better than
// what we currently have. For example:

// 1.
// this sugar
function MyComponent(props) {
  adopt foo from <Bar />;
  return <div>{foo}</div>;
}

bboy114crew

diff --git a/file.c b/file.c
index 6faa5a3..e3af329 100644
--- a/file.c
+++ b/file.c
@@ -1,26 +1,25 @@
 #include <stdio.h>
 
-// Frobs foo heartily
-int frobnitz(int foo)
+int fib(int n)

bboy114crew

import { Component } from "React";

export var Enhance = ComposedComponent => class extends Component {
  constructor() {
    this.state = { data: null };
  }
  componentDidMount() {
    this.setState({ data: 'Hello' });
  }
  render() {