Great design is a product of care and attention applied to areas that matter, resulting in a useful, understandable, and hopefully beautiful user interface. But don’t be fooled into thinking that design is left only for designers.

There is a lot of design in code, and I don’t mean code that builds the user interface—I mean the design of code.

Well-designed code is much easier to maintain, optimize, and extend, making for more efficient developers. That means more focus and energy can be spent on building great things, which makes everyone happy—users, developers, and stakeholders.

There are three high-level, language-agnostic aspects to code design that are particularly important.

1. System architecture—The basic layout of the codebase. Rules that govern how various components, such as models, views, and controllers, interact with each other.
2. Maintainability—How well can the code be improved and extended?
3. Reusability—How reusable are the application’s components? How easily can each implementation of a component be customized?

In looser languages, specifically JavaScript, it takes a bit of discipline to write well-designed code. The JavaScript environment is so forgiving that it’s easy to throw bits and pieces everywhere and still have things work. Establishing system architecture early (and sticking to it!) provides constraints to your codebase, ensuring consistency throughout.

One approach I’m fond of consists of a tried-and-true software design pattern, the module pattern, whose extensible structure lends itself to a solid system architecture and a maintainable codebase. I like building modules within a jQuery plugin, which makes for beautiful reusability, provides robust options, and exposes a well-crafted API.

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