Why you should care
When switch statements have large sets of case clauses, it is usually an attempt to map two sets of data. A real map structure would be more readable and maintainable, and should be used instead.
How we detect
CAST Highlight triggers this code insight when the average number of cases for switches found into a source file exceeds 3.
func main() {
i := 2
fmt.Print("Write ", i, " as ")
switch i {
case 1:
fmt.Println("one")
case 2:
fmt.Println("two")
case 3:
fmt.Println("three")
case 4:
fmt.Println("four")
case 5:
fmt.Println("five")
}
}
// 5 cases - 3 = 2
func main() {
fmt.Print("Go runs on ")
switch os := runtime.GOOS; os {
case "darwin":
fmt.Println("OS X.")
case "linux":
fmt.Println("Linux.")
case "webOS":
fmt.Println("WebOS.")
case "otherOS":
fmt.Println("otherOS.")
default:
// freebsd, openbsd,
// plan9, windows...
fmt.Printf("%s.\n", os)
}
}
// 4 cases - 3 = 1
func main() {
switch time.Now().Weekday() {
case time.Saturday:
fmt.Println("Today is Saturday.")
case time.Sunday:
fmt.Println("Today is Sunday.")
case time.Friday:
fmt.Println("Today is Friday.")
default:
fmt.Println("Today is a weekday.")
}
}
// There is 2 switch containing more than 3 cases
// so average is (2+1) / 2 (total switch) = 1.5 => rounded to 2
References
About CAST and Highlight’s Code Insights
Over the last 25 years, CAST has leveraged unique knowledge on software quality measurement by analyzing thousands of applications and billions of lines of code. Based on this experience and community standards on programming best practices, Highlight implements hundreds of code insights across 15+ technologies to calculate health factors of a software.