background preloader

Design pattern

Facebook Twitter

DevTools: State Of The Union 2015. Use your singletons wisely. Develop and deploy your nextapp on the IBM Bluemixcloud platform.

Use your singletons wisely

Start building for free The programming community discourages using global data and objects. Still, there are times when an application needs a single instance of a given class and a global point of access to that class. The general solution is the design pattern known as singletons. However, singletons are unnecessarily difficult to test and may make strong assumptions about the applications that will use them. Automated unit testing is most effective when: Coupling between classes is only as strong as it needs to beIt is simple to use mock implementations of collaborating classes in place of production implementations Certainly, when classes are loosely coupled, it is possible to concentrate on testing a single class independently. Unit tests are meant to ensure that each class behaves as it claims: independently of the rest of the system. Listing 1. Singletons know too much Where's the harm?

Back to top Listing 2. Learning JavaScript Design Patterns. Design patterns are reusable solutions to commonly occurring problems in software design. They are both exciting and a fascinating topic to explore in any programming language. One reason for this is that they help us build upon the combined experience of many developers that came before us and ensure we structure our code in an optimized way, meeting the needs of problems we're attempting to solve.

Design patterns also provide us a common vocabulary to describe solutions. This can be significantly simpler than describing syntax and semantics when we're attempting to convey a way of structuring a solution in code form to others. In this book we will explore applying both classical and modern design patterns to the JavaScript programming language. Target Audience This book is targeted at professional developers wishing to improve their knowledge of design patterns and how they can be applied to the JavaScript programming language. Acknowledgments Credits Reading We already use patterns everyday.

Pro JavaScript Design Patterns - Dustin Diaz, Ross Harmes - Google Livres. As a web developer, you’ll already know that JavaScript is a powerful language, allowing you to add an impressive array of dynamic functionality to otherwise static web sites.

Pro JavaScript Design Patterns - Dustin Diaz, Ross Harmes - Google Livres

But there is more power waiting to be unlocked—JavaScript is capable of full object–oriented capabilities, and by applying object-oriented principles, best practices, and design patterns to your code, you can make it more powerful, more efficient, and easier to work with alone or as part of a team. With Pro JavaScript Design Patterns, you’ll start with the basics of object–oriented programming in JavaScript applicable to design patterns, including making JavaScript more expressive, inheritance, encapsulation, information hiding, and more. With that covered, you can kick–start your JavaScript development in the second part of the book, where you’ll find detail on how to implement and take advantage of several design patterns in JavaScript, including composites, decorators, façades, adapters, and many more. Design Patterns Book. JavaScript Module Pattern: In-Depth.

The module pattern is a common JavaScript coding pattern.

JavaScript Module Pattern: In-Depth

It’s generally well understood, but there are a number of advanced uses that have not gotten a lot of attention. In this article, I’ll review the basics and cover some truly remarkable advanced topics, including one which I think is original. The Basics We’ll start out with a simple overview of the module pattern, which has been well-known since Eric Miraglia (of YUI) first blogged about it three years ago.

If you’re already familiar with the module pattern, feel free to skip ahead to “Advanced Patterns”. Anonymous Closures This is the fundamental construct that makes it all possible, and really is the single best feature of JavaScript. (function () { // ... all vars and functions are in this scope only // still maintains access to all globals }()); Notice the () around the anonymous function. Global Import JavaScript has a feature known as implied globals. Luckily, our anonymous function provides an easy alternative.

Module Export. Module pattern en JavaScript. Aujourd'hui, le JavaScript est devenu incontournable surtout pour les développeurs web.

Module pattern en JavaScript

Cependant, il reste encore trop méconnu et mal utilisé par la plupart des programmeurs, qui ne prennent pas vraiment le temps de l'étudier. Nombreux sont les projets web où le JavaScript est codé "comme on peut" dans un coin de la page HTML voire directement dans les éléments HTML. Ce design pattern, que je vais vous présenter, vous permettra d'avoir une approche différente sur la façon de structurer le JavaScript dans vos projets afin d'améliorer l'évolutivité et la maintenabilité de votre code.

Bonne lecture ! Il est recommandé d'être à l'aise avec JavaScript (et d'avoir de bonnes notions objets) afin d'aborder sereinement ce tutoriel. Rappels Je vous fais un petit récapitulatif des éléments que vous devez connaitre pour continuer la lecture. Portée des variables Les variables déclarées avec le mot-clé var dans une fonction, ne sont pas accessibles en dehors de celle-ci. Fonctions dans des fonctions Oui !