RenaudRohlinger

import React, { useEffect } from 'react'
import gsap from 'gsap'
import { useFrame } from '@react-three/fiber'

// sync gsap raf to r3f raf
gsap.ticker.remove(gsap.updateRoot)

export const GsapTicker = () => {
  const pg = React.useRef(0)
  gsap.ticker.remove(gsap.updateRoot)

northamerican

// Simple caching in Javascript using the new Logical nullish assignment (??=) operator

class FibClass {
  // Private field to store a value
  #fib = null

  // Fibonacci sequence method (recursive calculation)
  f (n) {
    return n < 3 ? 1 : this.f(n - 1) + this.f(n - 2)
  } 

mjackson

import React from "react";

export type ColorScheme = "light" | "dark";

export default function useColorSchemePreference(
  defaultColorScheme: ColorScheme = "light"
) {
  let darkQuery = "(prefers-color-scheme: dark)";
  let [colorScheme, setColorScheme] = React.useState<ColorScheme>(
    typeof window === "object" && window.matchMedia

coleturner

Demo

Context

useViewportScroll is a great way to create a parallax effect as the page scrolls. In some cases however, we only want to scroll when an element is in the viewport area.

So for example, if we have a "landscape" scene, and want to animate the Sun object only when it's in view, we start with our useViewportScroll implementation:

function Sun(props) {
 const { scrollY, scrollYProgress } = useViewportScroll();

theodorosploumis

Profile	download (kb/s)	upload (kb/s)	latency (ms)
Native	0	0	0
GPRS	50	20	500
56K Dial-up	50	30	120
Mobile EDGE	240	200	840
2G Regular	250	50	300
2G Good	450	150	150
3G Slow	780	330	200

slikts

Advanced memoization and effects in React

Memoization is a somewhat fraught topic in the React world, meaning that it's easy to go wrong with it, for example, by [making memo() do nothing][memo-pitfall] by passing in children to a component. The general advice is to avoid memoization until the profiler tells you to optimize, but not all use cases are general, and even in the general use case you can find tricky nuances.

Discussing this topic requires some groundwork about the technical terms, and I'm placing these in once place so that it's easy to skim and skip over:

• Memoization means caching the output based on the input; in the case of functions, it means caching the return value based on the arguments.
• Values and references are unfortunately overloaded terms that can refer to the low-level implementation details of assignments in a language like C++, for example, or to memory

ryanflorence

Everything I Know About UI Routing

Definitions

1. Location - The location of the application. Usually just a URL, but the location can contain multiple pieces of information that can be used by an app
   1. pathname - The "file/directory" portion of the URL, like invoices/123
   2. search - The stuff after ? in a URL like /assignments?showGrades=1.
   3. query - A parsed version of search, usually an object but not a standard browser feature.
   4. hash - The # portion of the URL. This is not available to servers in request.url so its client only. By default it means which part of the page the user should be scrolled to, but developers use it for various things.
   5. state - Object associated with a location. Think of it like a hidden URL query. It's state you want to keep with a specific location, but you don't want it to be visible in the URL.

mjackson

import { useEffect, useState } from 'react';

export default function useMediaQuery(query, defaultValue) {
  const [matches, setMatches] = useState(defaultValue);

  useEffect(() => {
    const mql = window.matchMedia(query);

    setMatches(mql.matches);

rybon

const compressGraphqlDocument = graphqlDocument =>
  graphqlDocument
    .replace(/#.*\n/g, '')
    .replace(/[\s|,]*\n+[\s|,]*/g, ' ')
    .replace(/:\s/g, ':')
    .replace(/,\s/g, ',')
    .replace(/\)\s\{/g, '){')
    .replace(/\}\s/g, '}')
    .replace(/\{\s/g, '{')
    .replace(/\s\}/g, '}')

remy

import { withRouter } from 'next/router';
import Link from 'next/link';
import React, { Children } from 'react';

const ActiveLink = ({ router, children, ...props }) => {
  const child = Children.only(children);

  let className = child.props.className || '';
  if (router.pathname === props.href && props.activeClassName) {
    className = `${className} ${props.activeClassName}`.trim();