Go simple error enums // Coding & Running

Edit 1

There are a few cases the previous way can go sideways so something like this would be more appropriate:

Definition

var (
    ErrMissingValue = errors.New("missing value")
    ErrWrongValue   = errors.New("wrong value")
)

Usage

if err := f(); errors.Is(err, ErrMissingValue) {
    // handle error
}

Original

Here is my take on having a consistent error API throughout the program.

From searching around, most of the ways described are really complicated in my opinion for doing this, so here is what I’m using:

Definition

type ErrorMessages struct {}
func (e ErrorMessages) MissingValue () string { return "missing value" }
func (e ErrorMessages) WrongValue () string { return "wrong value" }

Usage

if err.Error() == (ErrorMessages{}.MissingValue()) {
  log.Println(ErrorMessages{}.MissingValue())
}