A Quantum Immortal

1. If you’re not interested in web development, you can stop here.
2. Go spend 10 minutes reading this post.

A few things I’ve learned:

1. Open chrome dev tools, click the gear icon to the bottom right, and take a look at the options … I never bothered to do it, but it’s worth going over this.
2. Going to try Dock To Right … I always feel there’s not enough room at the bottom of the screen, and it doesn’t have to be this way.
3. Hitting Ctrl+Shift+F will search all js sources. I’ve wished for this features for a long time and didn’t know it existed!
4. Ctrl+O will let you lookup a specific source file … much more convenient than browsing through the list of sources.

• Yeoman– A system for bootstrapping & managing Node.js based projects. Looks yummy. Backed by Google Engineers.
  • How to install on Windows
  • This inspired me to write this question on Quora – Will Node.js be a major winner of the “Battle of the web servers”
  • Also, are there other similar Node/javascript frameworks?
• Why Dropbox have switched to CoffeeScript (in a week!)
• Another Intro to Ember.js (40 minute vid)
• Build your own custom jQuery (3:40 minute vid)
• Bower – a “package manager for the web”. Bower lets you easily install assets such as images, CSS and JavaScript, and manages dependencies for you.
• Notifier.js – yet another simple notification system for your webapp.

Summary of JSW 90:

• A critical review of ECMAScript 6 quasi-literals
• Battle of the top 7 JS application frameworks – a fantastic, must-read article for any Javascript developer (you can skip the detailed comparison at the end if you don’t have the time)
• Intro to Require.js – I skipped this one for time considerations, but it looks well-written.
• gridster.js – easily create a grid layout. Nifty demo.
• trunk8 – smart text truncation library.

My choice of interesting links for this time is:

• TodoMVC and Intro to JS MVC frameworks
• Migrating from jQuery to Backbone, step by step (bonus: $.proxy)
• On packaging JS components

I recently subscribed to Javascript Weekly, a weekly newsletter (yes, no RSS! or RSS feed) rather high quality weekly collection of Javascript cool stuff.

I’ve been picking the best links and sending to people at work, when I thought … hmm, I actually have a blog, why not summarize it here instead?
So, whenever I feel like it, I’ll be posting my own picks out the this week’s JS weekly.

Today, we have:

• Select2, an awesome replacement of HTML <select> boxes.
• jQuery 1.9/2.0 – the TL;DR edition
• Breaking the JavaScript Speed Limit with V8 (vid, I only skimmed it)
• Wakanda reaches 1.0 – A full stack JS environment (Server, DB, even IDE). For JS nuts (I’ll be sticking with my IntelliJ for now, thanks).
• Modern JavaScript engines can defer the parsing process of a function body until it is completely needed
• jam – package manager building on top of require.js  (“jam upgrade jquery”)
• The new sizzle (jQuery CSS selector engine). Did you know it was extensible? (You can code in and precompile custom selectors!)
• 5+1 reasons to choose AngularJS as your client-side templating / MVC framework

Hi all, this is your newb web developer talking again. While some of the following might be obvious to the more experienced web devs among you, this is a post that I wish I’d read when I just started using jQuery.

Write your own jQuery plugins

The word “plugin” usually entails something complicated and with some non-trivial learning curve (e.g. how many of you ever wrote a Chrome of Firefox plugin?) Well, in jQuery, this is really not the case. Here is how you write a simple jQuery plugin:

$.fn.enable = function() {
  $(this).prop("disabled", false);
};
 
$.fn.disable = function() {
  $(this).prop("disabled", true);
};

I find it useful to wrap even simple one liners such as .prop(“disabled”, false) with a plugin, because the semantics of writing $(“#foo”).disable() is much nicer than playing with properties/attributes directly. I haven’t written a lot of plugins yet, but it’s something to keep in mind as a useful tool to wrap actions on specific DOM elements.

Know the commonly used plugins
There are a ton … I still know very few of them. Here are a bunch of useful ones (and the ones I personally know and use).

A lot of plugins are very easy to use, and have good documentation and demos, so not using them and rolling your own solution is usually just a result of ignorance. Take the time to educate yourself!

UI Queues
For a long time I’ve that you can do things like $(“#mydiv”).show(), $(“#mydiv”).hide() and even $(“#mydiv”).show(1000) for a simple animation. Only recently I discovered you can actually chain these using Event Queues:

$("#mydiv")
  .hide(1000)
  .delay(500)
  .show(200)
  .fadeOut();

Each call to an animation method gets queued up and executes after the previous one.

Deferred
jQuery Deferred is a little gem. It lets you write fluent code similar to the queue example above. Here is how you use it:

$.when($.post('http://api.com/request_1'), 
       $.post('http://api.com/request_2'))
  .then(function(){alert("Got two responses")});

You can also use them with the event queue:

  $("#mydiv")
    .show(1000)
    .delay(500)
    .promise()
    .then(function(){/*do something */});

That’s all I have for now. Have any essential tips & tricks that I’m missing out on?

I’ve been refactoring code all my professional career. I started from C/C++, and when I hit C# (Resharper) and Java (IntelliJ), my productivity at refactoring was boosted by a few factors by the wonderful IDEs and refactoring tools that these languages have.

I am rather confident when I write “dirty code” in Java or C#, because I know that I can swiftly refactor it into beautiful code without too much trouble. Both aforementioned IDEs are so great at this, that it’s painless. You can take an ugly 300 line method and break it into several methods, break a long class into several classes, inline, move, and otherwise shape your code.

Enters javascript and web development.

Last year I’ve made the plunge and officially started working on front end web development, first at Google, and recently at Commerce Sciences. And I’ve recently discovered that … refactoring javascript and frontend code is hard.

The language is dynamically typed

Compilers and IDEs can help you less when the language is dynamic. They can make less assurances about your code, making reasoning and refactoring harder. Safely moving a method from class Foo to class Baz is an easy feat in a statically typed language, and a difficult or impossible one in a dynamic language.

Classes are not first-class citizens

While you can do OOP in javascript, classes are not first class citizens, but rather they’re implemented using functions, objects and prototypes. Automatically reasoning about “classes” without having an equivalent of keyword class is difficult.

Your code is not just Javascript, it’s HTML & CSS as well

Web development is not just about javascript, it’s a combination of JS, HTML & CSS (not to mention other potential technologies such as LESS/SCSS, HAML, JSON, and whatever language your backend is written in). Unless you’re already a web development ace and perfectly design your codebase … you will get these mixed up. Refactoring is about changing the design of your program, and when that design is split up between three or four different technology domains, design mistakes are harder to rectify.

You can’t (at least not yet) do an automatic refactoring to “move inline css into an external css file”, or to “convert static html snippet into a javascript DOM manipulation method”. The makers of IDEs and refactoring tools don’t have javascript completely figured out yet, no wonder they haven’t gotten around to building cross-domain refactoring!

Again, if you “know what you’re doing”, you can structure your program perfectly in the first place, and won’t ever have to do this kind of “cross domain refactoring”. Sadly, we’re not all born with this kind of experience.

It’s harder to know when you’ve broken something

Backend code is so much easier to test than frontend code. While frontend testing is important, and growing, it is by no means as well understood or practiced as classical “backend TDD, this is a calculator, assertEquals(30, calc.plus(10, 20))”.

So, since BE code has much wider test coverage than FE code, and is bloody compiled for Java & C#, when you refactor FE code it has a much greater chance of breaking down, often in subtle ways you’ll only notice on IE 8, or when the network is slow, or whatever edge case surfaces your particular bug.

So … how do we manage?

• Refactor less – Since we know refactoring is hard, we try to do less refactoring and more pre-factoring. Think a little more than usual before coding. While I’ve grown the habit of “code first, think about design later” over the years due to power of refactoring, it’s less useful in FE dev, so I need to take the time before coding and try harder to get it the design right on my first attempt.
• Still .. refactor – IntelliJ and Resharper both offer some refactoring capabilities. I’m most comfortable with “limited scope refactoring” – those that affect one function like Extract Variable. Use the tools you do have, instead of whining about the tools you don’t.
• Try to think harder about the different problem domains (JS/HTML/CSS), and to develop a better understanding of how to structure your program in a way that won’t force you do to refactoring across problem domains.

Please do share your own experience with refactoring in web dev!

Thread.sleep() has always been considered a “bad thing” in programming, something you do when you don’t have a good alternative. You could sleep() when you’re polling for a long operation, but the better solution would always be to get a notification when the operation completes, to avoid blocking a thread and generally wasting time – if the operation finished in 600 milliseconds, and you poll only every second, then you completely wasted 400 milliseconds, right?

Well, it turns out there is at least one use case where you really should waste those extra 400 milliseconds – User Interface.

I recently implemented a web UI component that checks if another website is reachable, and only then proceeds. If the website is not reachable, the user has to stay on that page and try again (perhaps he mistyped the URL). I implemented a server method that checks if the URL is alive, and called it from the client side via AJAX. The code looks something like this:

showLoadingIcon(); // displays a "loading" GIF
$.post(url, function(result) {
  hideLoadingIcon();
  if (result.good) {
    // proceed
  } else {
    // Display error message
  }
});

Well, it turns out that while this code is perfectly correct and efficient, it feels erratic from a usability perspective. If the page took a long time to access, it would behave fine, but if the page was very quick, and the method returned within say 200 milliseconds, the “loading” icon would flicker, creating an annoying experience for the user.

The solution is adding a manual, “artificial” sleep(). If the loading was long, no sleep was necessary, but if it was too short, I added a call to setTimeout, to ensure the loading image is always spinning for at least a full second.

While this is not really an example of Thread.sleep() (that doesn’t really have a javascript equivalent), this does show that sometimes delaying an interaction is required to reduce the user’s pain or confusion.