remarkablemark

JavaScript Classes - ES5 vs ES6

An example that shows the difference between creating a JavaScript class and subclass in ES5 and ES6.

Reference

longtimeago

How to squash commits in a GitHub pull request

o you've contributed some code to an open source project, say, Rails. And they'd like you to squash all of the commits in your pull request. But you're not a git wizard; how do you make this happen?

Normally, you'd do something like this. I'm assuming upstream is a git remote that is pointing at the official project repository, and that your changes are in your 'omgpull' branch:

andrey-skl

To run on ios:

1. Install XCode (recommended) or XCode command line tools by xcode-select --install
2. Into XCode settings, go to "Downloads" tab and download iOS 9.2 emulator
3. Compile native app and run it on simulator via npm run ios

To run on Android:

1. Set up Android environment
2. Create emulator via npm run android-emulator-create
3. Run emulator via npm run android-emulator
4. Compile native code and run it on emulator via npm run android

paulirish

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

chenglou

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:

chantastic

Hi Nicholas,

I saw you tweet about JSX yesterday. It seemed like the discussion devolved pretty quickly but I wanted to share our experience over the last year. I understand your concerns. I've made similar remarks about JSX. When we started using it Planning Center, I led the charge to write React without it. I don't imagine I'd have much to say that you haven't considered but, if it's helpful, here's a pattern that changed my opinion:

The idea that "React is the V in MVC" is disingenuous. It's a good pitch but, for many of us, it feels like in invitation to repeat our history of coupled views. In practice, React is the V and the C. Dan Abramov describes the division as Smart and Dumb Components. At our office, we call them stateless and container components (view-controllers if we're Flux). The idea is pretty simple: components can't

carols10cents

Thanks to @seejee for making this for me!!!

C# to Rust Cheat Sheet

The goal of this is to have an easily-scannable reference for the most common syntax idioms in C# and Rust so that programmers most comfortable with C# can quickly get through the syntax differences and feel like they could read and write basic Rust programs.

What do you think? Does this meet its goal? If not, why not?

Variables

obolton

AWS ELB with Node.js and WebSockets

This assumes that:

• You are using Nginx.
• You want to accept incoming connections on port 80.
• Your Node.js app is listening on port 3000.
• You want to be able to connect to your Node.js instance directly as well as via the load balancer.

####1. Create load balancer

yuval-a

NOTE: This document is OLD - and most of the tips here are probably outdated, since newer versions of Javascript have been
released over the years - with newer optimizations and more emphasis on optimizing newly supported syntax.


// Array literal (= []) is faster than Array constructor (new Array())
// http://jsperf.com/new-array-vs-literal/15
var array = [];

// Object literal (={}) is faster than Object constructor (new Object())
// http://jsperf.com/new-array-vs-literal/26

austinhyde

Observables

You don't really need a framework or fancy cutting-edge JavaScript features to do two-way data binding. Let's start basic - first and foremost, you need a way to tell when data changes. Traditionally, this is done via an Observer pattern, but a full-blown implementation of that is a little clunky for nice, lightweight JavaScript. So, if native getters/setters are out, the only mechanism we have are accessors:

var n = 5;
function getN() { return n; }
function setN(newN) { n = newN; }

console.log(getN()); // 5

setN(10);