jQuery Javascript large scale application development - javascript

I have just been asked to describe the architecture for a large scale dashbaord style project that i will be working on.
I have bever worked on a application of this size and am a bit lost as to what to say.
Could i be pointed in the direction of any articles that may help me get started and hopefully finished.
I have gleaned the following information thus far but i am not really sure that it describes the architecture.
1) Use classes instead of seperate functions and each class or group should be contained within their own JS file
2) Prior to production there should be a compile step where said JS files are compiled and minified
3) Step2 does not have to contain all the files. Jsut the common ones to start
4) Use a classloader to load classes, plugins etc when they are needed. On research could jQuery's getScript function be used for this or even a jQuery plugin loader:
http://api.jquery.com/jQuery.getScript/
http://www.unwrongest.com/projects/lazy/
Am feeling way out of my depth at the mo so any help would be massively appreciated. Be honest, if the above is competely irrelevant then i guess i am in the wrong job :(

Everything you need to know can be found here:
http://addyosmani.com/largescalejavascript/
Create a library of loosely couple components that communicate through an application controller (e.g. event bus).

I would recommend looking at using ExtJS 4 for this. Its APIs and development methodology closely track what you would expect from .NET or Java for developing a large-scale desktop app.
Version four answers all four of your points. It has...
1) A system for defining Java/C#-like classes in Javascript that work almost exactly the way a Java or C# developer would expect.
2) Dynamic resource loading.
3) The ability to create a final product from the SDK which is a neat, compressed version which contains just what you need.

If you are to do this with pure Javascript, ensure you use some reference architecture in the job. What HDave pointed above is really good material. If you want a ready-made reference architecture as a project startup code, have a look at BoilerplateJS:
http://boilerplatejs.org
After some large-scale projects, I have compiled some of the learnings in to this framework. Look at the samples too. Some of the concerns you raised are already addressed in this codebase such as use of OO concepts, minification and optimizations, decoupled moduler design and many more too.

Related

What makes Angular and Backbone different from jQuery?

I have been using JavaScript and jQuery for quite a while now and want to extend my skill set further, during my search I came across two popular names Angular and Backbone and while reading about them I found one line common in both them which somehow also seems to be their USP i.e.
It is designed for developing single-page web applications
This makes my confused.
What is that I cannot do with JS or jQuery and I would require these?
I have created web application on single page, where users can perform CRUD operations on single page through asynchronous calls so why so much importance of for these others libraries?
And as a middle level web developer who has have good hands on JS is it right path to move to these two or here is something else I should look into before these?
Please help?
Structure.
In an ongoing project that started about 4 years ago we built the front end with jQuery. We were able to do just about everything that we needed creating several single page applications that were quite functional.
As the project progressed and the code base grew we started experiencing some major problems with maintainability of the code. We ended up with hundreds or thousands of lines of JavaScript code per page in a tangle that was almost impossible to navigate. This could have been avoided if we were more careful of course but at the time we focused on making sure the back end architecture was robust.
Many years ago the community learned that code needs structure to be maintainable. We developed MVC patterns, multi-tiered applications etc. But JavaScript was never a big player in the field and we largely ignored it.
Over the last 6 months or so we introduced Angular into the project and started sorting out some of the mess in the project. The results are remarkable. Not only is the code simpler and easier to create, the structure makes it easier to implement tests, easier to maintain and generally a huge improvement over what we had before. We still use jQuery but now we have been burnt by the lack of structure and know a thing or two about the architecture of a JavaScript application. Angular and its like provide you with the tools to architect a good application.
When you are creating larger scale web applications it is wise to check out Backbone, Angular or perhaps Meteor. jQuery supports neat tricks, but it does not help you structure your code in a maintainable way. Larger scale web apps build on jQuery need their own vision on how to separate the code into layers with their own responsibility.
The other frameworks give more support.
I would suggest checking out at least one of the libraries. Perhaps you eventually won't use them, but it will benefit how you work in jQuery.
Well Now a days there has been quite a hype about Angular.js and especially SPAs (Single Page Applications). Well to be honest, I had the same question in my mind about a month ago when my team decided to shift from Jquery to Angular.
Whenever it comes to Jquery, one of the first thing that comes in our mind is the DOM manipulation. While using Jquery we always think of manipulating the DOM. Show/hide elements, animating elements, getting data from tags you name it. But Angular offers something more than that. It offers you an architecture, a way to structure your applications at the front end.
So whenever you go for Angular.js, change the way you think about creating web applications (and believe me its worth it). Most of Angular's structure uses the concept of Dependency Injection which is a neat way to maintain your code.
Backbone is only a library whereas Angular.js is a complete framework to create and manage Single Page Applications
Talking about the fact that Angular.js should be used when we are creating large scalable apps, it is true. In my case the team I work with is full of Jquery Ninjas. We have been creating a great app for the last 3 years and believe me it became difficult for us to maintain and debug thousands of lines of Jquery. This is the main reason we have decided to revamp this app into Angular.
Kindly see some of these Helpful links. You will get a better idea.
http://net.tutsplus.com/tutorials/javascript-ajax/3-reasons-to-choose-angularjs-for-your-next-project/
"Thinking in AngularJS" if I have a jQuery background?

Ext JS - A start

Folks,
I am starting off to learn ExtJS. I had a look through Sencha's website. I went through some of the questions also already asked here.
But had some doubts,
What is the difference between ExtJS designer and Aptana ? Do we require both ?
How to start building your own 1st application in ExtJS ? Any tutorials for the total beginners.
Will I need to write JavaScript code manually or use a ExtJS designer to do that for me ?
Thanks.
I'll disagree a bit with the already-accepted answer.
They are both optional. I use neither.
OK, not too helpful. Aptana is a general-purpose IDE. It is based on Eclipse, but unlike vanilla Eclipse (which is Java-oriented) Aptana has lots of additions and plugins for doing JavaScript, PHP and other "web-centric" development. I actually use Aptana myself, even for Ext development, because it works for me. IDE discussions tend to get religious -- everyone has their own requirements and peeves, YMMV. Aptana does actually support framework-specific autocomplete, including for Ext JS (though I think they are still on an older version). Note that you can accomplish the same things as Aptana (generally-spekaing) using WebStorm, Komodo, NetBeans, TextMate or any old text editor -- just depends on what IDE-specific features you find helpful or not.
Ext Designer (now Sencha Architect) on the other hand is NOT a general-purpose IDE -- it is strictly intended as an Ext UI design tool. However, it does go beyond simply "placing widgets" on the page. You can easily drag-drop things into place and also preview how they will render, hook up data stores to databound widgets (again via simple drag/drop interactions), it includes context-specific config and property setting (which makes it much easier to know what options are available without having to refer to the API docs constantly), etc. Architect then generates classes, in best-practice code format, that you can drop into your app and then extend as needed with your own business logic. The output of Architect could basically become the input project for Aptana (or whatever) where you would build your application code (although many people stick exclusively to Architect).
Regarding tutorials, the docs site of Sencha.com was revamped recently and includes many tutorials updated for the most current versions of Ext. Of course the official examples are also a good place to start. The best book on Ext development is probably Jay Garcia's Ext JS in Action, though unfortunately it has not yet been updated for Ext 4 (he's currently working on that). It's a great overview of the concepts and best practices for Ext in general though, and a lot of what's in that book will still apply today.
Finally, while Architect will definitely get you started with good UI code, it will not wire your app together or write any business logic for you. For that, you'll have to use the existing tutorials and examples to help guide you to write your own code.
They are both optional. I use neither.
Depends on how “total” a beginner you are. Judging from your questions, I guess you aren’t familiar with JavaScript and web development in general. If that is the case, start by reading some tutorials on JavaScript and AJAX—you’ll need a solid grounding in those to make good use of Ext JS. I am yet to see a good tutorial for Ext JS (version 4) itself, and you’ll probably end up gathering pieces from the official docs, the Sencha blog, and the examples that ship with Ext JS.
You will have to write JavaScript (and maybe also HTML and CSS, depending on your scenario). The designer can only help you with placing widgets (like buttons or text boxes) on the page. In my experience so far, this has been the easy part, so unless you’re doing a complex user interface, you probably don’t need the designer.

Javascript: How to make sense of all the frameworks and design philosophies?

I have been a user of jQuery (and some of its minor plugins) for a while. The Javascript code I've developed over the years could be described best as... messy. It used a ton of global variables and functions here and there, didn't use standard ways of organizing the code, nor any design patterns whatsoever.
I am currently building the new version of a website, and I have completed doing the backend with PEAR::MDB2 and Smarty templates. The rest is just homebrew PHP with some classes.
Now I am at the point where I'll add the Javascript layer on top of the website to improve the user-friendliness of some features. (while making sure everything degrades gracefully) I want to write better, cleaner, more organized Javascript than I used to, so I did a little research. I read Stefanov's Object-Oriented Javascript to have a better grasp on some concepts I knew only loosely about (prototypes, constructors, etc.) as well. Now I'm stuck at a point where I wonder which Javascript frameworks I should use, and how to organize it all.
After conducting my research, I understood Cappuccino & Objective-J, and Sproutcore were not what I was looking for. To quote Cappucino's about page:
Cappuccino is not designed for building web sites, or making existing sites more "dynamic". We think these goals are too far removed from those of application development to be served well by a single framework. Projects like Prototype and jQuery are excellent at those tasks
So there's that. Then I found out about Coffee Script, which is more of a one-to-one "compiler" and wouldn't help me with the actual organization of my code.
I also stumbled on some articles that give guidelines:
Using Inheritance Patterns to Organize Large jQuery Applications
A JavaScript Module Pattern
I also found out about Backbone.js, Shoestring, JavaScriptMVC, Google Loader, jQuery Tools, jQuery UI. I don't really know what to do of all this... The things I know:
I don't want to invest too much time in learning something too complex, I want to keep things simple and flexible as much as possible (that is why I don't use Symfony on the backend, for example), yet clean and organized.
I want to use jQuery, the question is, what should I use with it? (that is compatible too)
Right now, I'd use jQuery and jQuery Tools and "organize" all that in a simple namespace/object literal with simple properties and methods and also, since the site is localized, I just plan on using the simple vsprintf (as I do on the backend) with key:value pairs loaded from an object literal provided by the backend. JavaScriptMVC seems interesting, but I fear it would bring way too much complexity for a project that is fairly small sized. That is where I need your advice! Thank you very much in advance.
Ok, my attempt at an answer:
There is no 'best' to way to do it. You now know what's there and I think you might have a preference for yourself for what you want. In that case, pick a framework and learn it inside-out. (sorry to burst your bubble, but each framework has a learning curve, some steep, some very easy, but in the end to use it well you have to invest in it. Just do it, you won't be sorry).
You of course have an preference for clean code, so you might take some considerations into account. You also say you have a preference for jQuery, which is fine, but there are some limitations (as also pointed out in the link provided by eskimoblood).
There are some nice lectures / and tutorials with advice on how to structure your code in jQuery:
How to manage large jquery apps
On Large jQuery apps
Essential Javascript and jQuery patterns (free ebook)
Some style guides:
Jquery core UI Styleguide
Google Closure Javascript Style Guide
Tools for checking your code
JSLint
JSHint (a more forgiving/practical fork)
Closure Linter (haven't tried it yet, but intend to)
Standard works (javascript)
Everything by Douglas Crockford
Quirksmode
There might be more.. perhaps more people can contribute, but I also think that you've almost reached the end of what you can learn before getting your hands dirty. Many of these guides are written in a very generic way, but the interesting thing is that javascript is called upon in many specific situations. It might be useful to just post some of the code that you regard as "messy" and we can help you figure out how to do it better. Good luck!
You should watch the video and read the links in this article and then you should ask yourself again if jquery is the right tool. Maybe you will use dojo, that is much better for larger projects or you take a look at backbone and where you can stay with jquery. After all both of them are more "javascriptish" then something like sproutcore, cappuciono or even GWT. And also much easier to understand when you come from jquery.
One framework that is to consider is definitely ReactJS from Facebook. This framework is pretty slick in many ways.
First thing you have to know is that it is a view framework. It can be used server-side to do the pre-rendering of pages, but it really shines on client side. Since it's a view framework, it can be used with backbone or any other "back-front"-end framework.
One of the main point of React is its rapidity. It keeps a virtual DOM in memory and virtualize all the webpages events. So the virtuals event are used to keep events browser agnostics.
The virtual DOM kind of make programming a dynamic site as if you were programming an old static website. You can just shoot the whole HTML to render to the view engine (as if you were "re-rendering" the whole page) and it will manage the DOM operations. It does a diff between the new virtual DOM and the current virtual DOM and only inserts nodes that needs to be inserted. This way you reduce the number of DOM ops and thus increase your render speed by a lot.
A good place to start is this tutorial which shows how to use "Flux" (the web flow designed by Facebook for its site) in order to realize a Todo application!

Architecture of a single-page JavaScript web application?

How should a complex single-page JS web application be structured on the client-side? Specifically I'm curious about how to cleanly structure the application in terms of its model objects, UI components, any controllers, and objects handling server persistence.
MVC seemed like a fit at first. But with UI components nested at various depths (each with their own way of acting on/reacting to model data, and each generating events which they themselves may or may not handle directly), it doesn't seem like MVC can be cleanly applied. (But please correct me if that's not the case.)
--
(This question resulted in two suggestions of using ajax, which is obviously needed for anything other than the most trivial one-page app.)
MVC architecture of PureMVC/JS is the most elegant IMO. I learned a lot from it. I also found Scalable JavaScript Application Architecture by Nicholas Zakas helpful in researching client side architecture options.
Two other tips
I've found view, focus, and input management are areas that need special attention in single page web apps
I also found it helpful to abstract away the JS library, leaving door open to change mind on what you use, or mix & match should the need arise.
Nicholas Zakas's presentation as shared by Dean is a very good place to start with. I was also struggling to answer the same question for a while. After doing couple of large scale Javascript products, thought of sharing the learnings as a reference architecture in case someone needs it. Have a look at:
http://boilerplatejs.org/
It addresses common Javascript development concerns such as:
Solution structuring
Creating complex module hierarchy
Self contained UI components
Event based inter module communication
Routing, History, Bookmarking
Unit Testing
Localization
Document Generation
etc.
The way I build apps:
ExtJS framework, single page app, every component defined in a separate JS file, loaded on-demand
Every component contacts its own dedicated web service (sometimes more than one), fetching data into ExtJS stores or special-purpose data structures
The rendering uses standard ExtJS components, so I can bind stores to grids, load forms from records, ...
Just choose a javascript framework, and follow its best practices. My favorites are ExtJS and GWT, but YMMV.
Do NOT roll your own solution for this. The effort required to duplicate what modern javascript frameworks do is too big. It is always faster to adapt something existing than to build it all from scratch.
Question - What makes an application complex ?
Answer - The use of word 'complex' in the question itself. Hence, a common tendency will be to look out for a complex solution right from the beginning.
Question - What does the word complex means ?
Answer - Anything that is unknown or partially understood. Example : The theory of Gravity even today is COMPLEX to me but not to Sir Isaac Newton who discovered it in 1655.
Question - What tools can I use to deal with complexity ?
Answer - Understanding and simplicity.
Question - But I understand my application . Its still complex ?
Answer - Think twice, because understanding and complexity does not co-exist. If you understand a huge huge application, I am sure you will agree that it is nothing but an integration of small and simple units.
Question - Why all of the above philosophical discussion for a question on
Single Page Application (SAP)?
Answer - Because,
-> SPA is not some kind of core technology that is newly invented for which we need to reinvent the wheel for a lot of things that we are doing in application development.
-> Its a concept driven by the need for better performance, availability, scalability and maintainability of web applications.
-> Its a fairly newly identified design pattern, so an understanding of SPA as a design pattern goes long way in making informed decisions about the architecture of a SPA.
-> At the root level no SPA is complex, because after understanding the needs of an application and the SPA pattern, you will realize that you are still creating an application, pretty much the same way you did before with some modifications and re-arrangements in the development approach.
Question - What about the use of Frameworks ?
Answer - Frameworks are boiler plate code / solution for some commonly identified and generic patterns, hence they can take off x% (variable, based on the application) load from application development but then not a lot should be expected out of them specially for heavy and growing applications. Its always a good case to be in complete control of your application structure and flow but most importantly the code for it. There should be no grey or black areas in the application code.
Question - Can you suggest one of the many approaches to SPA architecture ?
Answer - Think of your own framework based on the nature of your application. Categorize application components. Look for an existing framework that is close to your derived framework, if you find it then use it, if you do not find it then I suggest going ahead with your own. Creating framework is quite an effort upfront but produces better results in long run. Some basic components in my SPA framework will be:
Data Source : Models / Collections of Models
Mark Up for presenting data : Templates
Interaction with the application : Events
State capturing and navigation : Routing
Utilities , widgets and plug-ins : libraries
Let me know if this helped in any way and good luck with your SPA architecture !!
The best thing to do is to look at example uses of other frameworks:
TodoMVC showcases many many SPA frameworks.
You can use javascript MVC framework http://javascriptmvc.com/
The web application that I am currently working on uses JQuery and I would not recommend it for any large single page web application. Most frameworks i.e. Dojo, yahoo, google and others use namespaces in their libraries but JQuery does not and this is a significant drawback.
If your web site is intended to be small then JQuery would be ok but if you intended to build a large site then I would recommend looking at all the Javascript frameworks available and deciding which one most meets your needs.
And I would recommend applying the MVC pattern to your javascript/html and probably most of your object model for the javascript could be done as the json that you actually return from the server through ajax and the javascirpt uses the json to render html.
I would recommend reading the book Ajax in action as it covers most of the stuff you will need to know.
I'm using Samm.js in several one page applications with great success
I would go with jQuery MVC
Check out http://bennadel.com/projects/cormvc-jquery-framework.htm Ben is pretty sharp and if you dig around on his blog he has some nice posts about how CorMVC is put together and why.
Alternative: take a look to ItsNat
Think in JavaScript but code the same in Java in server with the same DOM APIs, in server is way easier to manage your application without custom client/bridges because UI and data are together.
Or have a look at https://github.com/flosse/scaleApp
NikaFramework allows you to create single-page application. Also allows you to write HTML, CSS (SASS), JavaScript into separate files and bundle them into only one output file in the end.
I would recommend to explore Yeoman. It allow you to use existing "best practice" for your new project.
For example:
if you decide to use Angular.js, there is a Yeoman generator, that give you a structure for routing, views, services, etc. Also allow you to Test, minify your code, etc.
If you decide to use Backbone, checkout this generator

Dynamic JavaScript loading with compression

Although I am using the Zend framework, MooTools JS library and my questions revolves around them, this is a more generic question.
I am working on a web app, in which I am using many elements which are sometimes useful on other pages (for example OpenLayers related MooTools classes).
Mootools already allows this "segmentation" by "classing" (creating "Class"..) so I feel tha the next thing to do is to have separate JS file for every class, then send a request to a PHP page with the classes I want and get in return JS file with what I need.
At the same time this mechanism will minify and gzip and cache locally on the server (for future requests) and send me back this one file.
I didnt go into design yet and was wondering if such / similar solution is out there?
Alternatively I see libraries like labJS that speeds things up by multi threading the requests, this however does not complete the solution with minification and gzip (I have to take care of this server side with another complementary solution).
Is any one using similar dynamic JS "Class" loading solution?
Cheers,
Roman
I think the tool you want to look at is the minify project. Here's a description:
Minify is a PHP5 app that helps you
follow several of Yahoo!'s Rules for
High Performance Web Sites.
It combines multiple CSS or Javascript
files, removes unnecessary whitespace
and comments, and serves them with
gzip encoding and optimal client-side
cache headers.
It's very straightforward to use, and, say you have it installed in http://example.com/min/, and you have two files to compress:
/resources/js/lib/library.js
/resources/js/main.js
You would call this url:
http://example.com/min/b=resources/js&f=lib/library.js,main.js
And the code looks like:
<script type="text/javascript"
src="/min/b=resources/js&f=lib/library.js,main.js"></script>
So basically there is a consistent URI based way to merge files together.
I'm not familiar with zend and only somewhat familiar with mootools so take this with a larger-than-average grain of salt.
Wouldn't it be easier to have a process that generates/minifies all the possible combinations of the classes you have and then just request a particular combination? You could automate this with a script pretty easily.
Also, I've used the HyperCache and WP_Minify plugins for wordpress and they do pretty much everything you are talking about so you might want to look there for inspiration.
What you describe is pretty much what the YUI PHP Loader does, although it is tailored towards the YUI JavaScript library. However, the project is open-source under the BSD license so it is a good place to get some ideas to implement your own.
Do also have a look at Lissa (which is based on YUI PHP Loader) that is a generic JavaScript (and CSS) loader.

Categories