iansu

Create New App

JavaScript Template

npx create-react-app@next --scripts-version=@next --template=cra-template@next my-js-app

TypeScript Template

npx create-react-app@next --scripts-version=@next --template=typescript@next my-ts-app

slikts

Why using the children prop makes React.memo() not work

I've recently ran into a pitfall of [React.memo()][memo] that seems generally overlooked; skimming over the top results in Google just finds it mentioned in passing in a [React issue][regit], but not in the [FAQ] or API [overview][react-api], and not in the articles that set out to explain React.memo() (at least the ones I looked at). The issue is specifically that nesting children defeats memoization, unless the children are just plain text. To give a simplified code example:

const Memoized = React.memo(({ children }) => (<div>{children}</div>));
// Won't ever re-render
<Memoized>bar</Memoized>
// Will re-render every time; the memoization does nothing

sayjeyhi

kill -9 $(lsof -i:PORT -t) 2> /dev/null

sayjeyhi

import { race, cancel, take, fork, all, put, select } from 'redux-saga/effects';

export function* fetchDataForPage() {
  const userId = yield select(getUserId);

  try {
    if (!userId) {
      throw new Error('No user - aborting');
    }

gaearon

If you use server rendering, keep in mind that neither useLayoutEffect nor useEffect can run until the JavaScript is downloaded.

You might see a warning if you try to useLayoutEffect on the server. Here's two common ways to fix it.

Option 1: Convert to useEffect

If this effect isn't important for first render (i.e. if the UI still looks valid before it runs), then useEffect instead.

function MyComponent() {

MoienTajik

Regex For Iranian Phone Numbers

This regex supports all kinds of Iranian mobile phone numbers :

^(\+98|0)?9\d{9}$

---

edysegura

var scores = [1, 4, 6, 8];
var result = scores.reduce((total, score) => total + score) / scores.length;
console.log(result); // 4.75

zhiguangwang

Installing and running shadowsocks on Ubuntu Server

16.10 yakkety and above

1. Install the the shadowsocks-libev package from apt repository.

    sudo apt update
    sudo apt install shadowsocks-libev
   

2. Save ss.json as /etc/shadowsocks-libev/config.json.

MattMcFarland

Table of Contents:

• Why FLUX?
• About this Guide
• Library Dependencies
• Directory Structure
• store.js
• constants.js
• dispatcher.js
• actions.js
• app.js

acauamontiel

/*
 * Clearfix
 */
clearfix()
	&:before,
	&:after
		content ' '
		display table

	&:after