TL;DR: Don't pass more than three arguments to your functions.

Problems

• Low maintainability

• Low Reuse

• Coupling

• Readability

Solutions

• Find cohesive relations among arguments

• Create a "context".

• Consider using a Method Object Pattern.

• Avoid "basic" Types: strings, arrays, integers, etc, and think in terms of objects.

Exceptions

• Operations in the real-world needing no cohesive collaborators.

Sample Code

Wrong

class Printer {
    fun print(
        documentToPrint: String,
        paperSize: String,
        orientation: String,
        grayScales: Boolean,
        pageFrom: Int,
        pageTo: Int,
        copies: Int,
        marginLeft: Float,
        marginRight: Float,
        marginTop: Float,
        marginBottom: Float
    ): Unit = TODO()
}

Right

class PaperSize {
    //...
}

class Document {
    //...
}

class PrintMargins {
    //...
}

class PrintRange {
    //...
}

class ColorConfiguration {
    //...
}

class PrintOrientation {
    //...
}

class PrintSetup(
    paperSize: PaperSize,
    orientation: PrintOrientation,
    color: ColorConfiguration,
    range: PrintRange,
    copiesCount: Int,
    margins: PrintMargins
)

class Printer {
    fun print(
        documentToPrint: Document,
        setup: PrintSetup
    ): Unit = TODO()
}

Conclusion

Relate arguments and group them. Always favor real-world mappings. Find in the real world how to group the arguments into cohesive objects.

If a function gets too many arguments, some of them might be related to class construction. This is a design smell too.

Credits

• Code Smell 10 - Too Many Arguments by Maxi Contieri