# Other principles

* [Other principles](#other-principles)
  * [KISS - Keep it simple stupid](#kiss-keep-it-simple-stupid)
  * [Don’t Repeat Yourself (DRY)](#dont-repeat-yourself-dry)
  * [You Aren’t Gonna Need It (YAGNI)](#you-arent-gonna-need-it-yagni)

## KISS - Keep it simple stupid

* that code that is as simple as possible is better than code that is more complex.
* code that is less “elegant”, but more easily maintainable code, is better
* Is this code likely to be easily repairable by an average programmer working under pressure during a production defect/outage?

## Don’t Repeat Yourself (DRY)

* referred to as the “Single Source of Truth” or “Once and Only Once”
* as not doing copy-and-paste coding
* every piece of knowledge must have a single, unambiguous, authoritative representation within a system
  * any given concept or abstraction that the code embodies should be defined only once in one place and should be clear to the reader/maintainer.
* Can apply to hand written code or configuration
* If repeated three times, extract out
  * if the duplicated code represents an important concept/abstraction in the system then any duplication may be unacceptable
* Removing duplication, means you can give it a descriptive name

## You Aren’t Gonna Need It (YAGNI)

* for the resistance of the temptation to second-guess what code might be needed at some future point and adding it now, rather than adding it only when it is actually needed.
* Can result in
  * Bloated code: unused/unrequired code exists now, and may never be removed/refactored
  * Increased Cost: the unrequired code may still need testing and maintaining
  * Slipped dates: the unrequired code takes time away from other features that may impact overall delivery dates
  * Waste: by the time the unrequired code is actually required, it may no longer be valid if business requirements have changed in the meantime