Cognitive Complexity

Cognitive Complexity is a measure of how difficult a unit of code is to intuitively understand. Unlike Cyclomatic Complexity, which determines how difficult your code will be to test, Cognitive Complexity tells you how difficult your code will be to read and comprehend.

A method's cognitive complexity is based on a few simple rules:

• Code is not considered more complex when it uses shorthand that the language provides for collapsing multiple statements into one
• Code is considered more complex for each "break in the linear flow of the code"
• Code is considered more complex when "flow breaking structures are nested"

Further reading

• Cognitive Complexity docs
• Cognitive Complexity: A new way of measuring understandability

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trailing-whitespace

Flag whitespace after the last non-whitespace character on each line until the newline.

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let number = 42¬

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trailing-whitespace

Flag whitespace after the last non-whitespace character on each line until the newline.

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let number = 42¬

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let number = 42••¬

trailing-whitespace

Flag whitespace after the last non-whitespace character on each line until the newline.

Preferred

let number = 42¬

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let number = 42••¬

trailing-whitespace

Flag whitespace after the last non-whitespace character on each line until the newline.

Preferred

let number = 42¬

Not Preferred

let number = 42••¬

trailing-whitespace

Flag whitespace after the last non-whitespace character on each line until the newline.

Preferred

let number = 42¬

Not Preferred

let number = 42••¬

trailing-whitespace

Flag whitespace after the last non-whitespace character on each line until the newline.

Preferred

let number = 42¬

Not Preferred

let number = 42••¬

trailing-whitespace

Flag whitespace after the last non-whitespace character on each line until the newline.

Preferred

let number = 42¬

Not Preferred

let number = 42••¬

trailing-whitespace

Flag whitespace after the last non-whitespace character on each line until the newline.

Preferred

let number = 42¬

Not Preferred

let number = 42••¬

trailing-whitespace

Flag whitespace after the last non-whitespace character on each line until the newline.

Preferred

let number = 42¬

Not Preferred

let number = 42••¬

trailing-whitespace

Flag whitespace after the last non-whitespace character on each line until the newline.

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let number = 42¬

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let number = 42••¬

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func function1() {
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// a comment
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struct SomeStruct {

  func function3() {
    // something goes here
  }

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  var text = 2
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function1()
// a comment
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}

struct SomeStruct {
  func function3() {
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  func function4() {
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}
func function5() {
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}

trailing-whitespace

Flag whitespace after the last non-whitespace character on each line until the newline.

Preferred

let number = 42¬

Not Preferred

let number = 42••¬

trailing-whitespace

Flag whitespace after the last non-whitespace character on each line until the newline.

Preferred

let number = 42¬

Not Preferred

let number = 42••¬