# Readability

* [Readability](#readability)
  * [Naming booleans](#naming-booleans)
  * [Method length](#method-length)
  * [Remove Unused Code](#remove-unused-code)
  * [Nesting](#nesting)
  * [Naming Variables and Parameters](#naming-variables-and-parameters)
* Code is written for humans not compilers
  * compiler does not have to maintain the code over time - humans do.
  * Code needs to be easily understood for it to be soft
* Qualities of readable code
  * Makes crystal clear the programmer’s intent
  * Makes it easy for bugs to stand out
  * Can be easily understood and changed by other programmers
  * Creates fewer surprises and annoyances when being read
* Reduces the mental effort required to understand it and therefore be able to change it safely.

## Naming booleans

* The readability of logical constructs such as an if statement can often be improved by the introduction of a well-named, intermediary variable

  \`\`\`java

  if(ageInYears==40 && isEyeColorBlue && firstName=="Julia") { // etc. }

boolean isValid=ageInYears==40 && isEyeColorBlue && firstName=="Julia"; if(isValid) {} // etc. }

\`\`\`

* If the code is performing some action when something is invalid, it can make sense to rename the isXXX to isNotXXX so that the reader doesn’t have to think as much
  * ie use isNotValidPerson rather than !isValidPerson

## Method length

* Methods with lots of lines of code tend to be harder to understand than methods with fewer lines of code.
* Can set a number of lines but treat it as a guide, with the full knowledge that as the number of lines increases, readability decreases.
* Some methods will be very long, ie applying business logic in usecase. But accept this to keep all logic in one place

## Remove Unused Code

* Every line of code that needs to be read has a mental cost associated with it.
* IDE should help with this
* This includes commented out code
* Can always use source control to go back to it

## Nesting

* Multiple levels of nested code (ifs, loops, etc.) can reduce readability.
* Can use guard clauses, or extract method to reduce nesting

## Naming Variables and Parameters