Seyi Adebajo theseyi

Moral Concerns

JSONP is not actually JSON with padding, it's Javascript code that's executed. JSON is not a real subset of Javascript and the way it is not is important to us: via UTFGrid, we are all UTF-8 masters.

JSONP is not safe: it's Javascript that's executed. It's trivial to XSS with JSONP, because JSONP is XSS. Just have a call like mapbox.load('foo.tilejson', …) and if foo.tilejson gets replaced with destroyYoursite(), it gets run. Compare to JSON.parse, which is, on purpose, not eval.

Practical Concerns

JSONP is questionable in terms of performance. To be fast, you want to have the same callback all the time so that you can cache the response. But this leads to a page like

The introduction to Reactive Programming you've been missing

(by @andrestaltz)

This tutorial as a series of videos

If you prefer to watch video tutorials with live-coding, then check out this series I recorded with the same contents as in this article: Egghead.io - Introduction to Reactive Programming.

Spurred by recent events (https://news.ycombinator.com/item?id=8244700), this is a quick set of jotted-down thoughts about the state of "Semantic" Versioning, and why we should be fighting the good fight against it.

For a long time in the history of software, version numbers indicated the relative progress and change in a given piece of software. A major release (1.x.x) was major, a minor release (x.1.x) was minor, and a patch release was just a small patch. You could evaluate a given piece of software by name + version, and get a feeling for how far away version 2.0.1 was from version 2.8.0.

But Semantic Versioning (henceforth, SemVer), as specified at http://semver.org/, changes this to prioritize a mechanistic understanding of a codebase over a human one. Any "breaking" change to the software must be accompanied with a new major version number. It's alright for robots, but bad for us.

SemVer tries to compress a huge amount of information — the nature of the change, the percentage of users that wil

This post is also on my blog, since Gist doesn't support @ notifications.

Components are taking center stage in Ember 2.0. Here are some things you can do today to make the transition as smooth as possible:

Use Ember CLI
In general, replace views + controllers with components
Only use controllers at the top-level for receiving data from the route, and use Ember.Controller instead of Ember.ArrayController or Ember.ObjectController
Fetch data in your route, and set it as normal properties on your top-level controller. Export an Ember.Controller, otherwise a proxy will be generated. You can use Ember.RSVP.hash to simulate setting normal props on your controller.

Software is layered.

Documentation is not. If your documentation states

Run npm install foo to install this module

It is really saying

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

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

	/*
	* object.watch polyfill
	*
	* 2012-04-03
	*
	* By Eli Grey, http://eligrey.com
	* Public Domain.
	* NO WARRANTY EXPRESSED OR IMPLIED. USE AT YOUR OWN RISK.
	*/

	As asked by John on Twitter: https://twitter.com/johnallsopp/status/383461909640384512

	"wow. Animate change to left via CSS, ~500 paint/reflow events. Animate translateX - 16!"

	Answering here because it's a long response and I'm too slack to have a
	blog/tumble/plus/facebook/myspace.

	NOTE: This answer is out of date. See comment below.

	The easy answer is that changing left causes relayout, which triggers a repaint, while



	// Extend Ember.Route to add support for sensible
	// document.title integration.
	Ember.Route.reopen({

	// `titleToken` can either be a static string or a function
	// that accepts a model object and returns a string (or array
	// of strings if there are multiple tokens).
	titleToken: null,