wails/mkdocs-website/docs/en/development/changes_enums.md

Enums

In Go, enums are often defined as a type and a set of constants. For example:

type MyEnum int

const (
    MyEnumOne MyEnum = iota
    MyEnumTwo
    MyEnumThree
)

Due to incompatibility between Go and JavaScript, custom types cannot be used in this way. The best strategy is to use a type alias for float64:

type MyEnum = float64

const (
    MyEnumOne MyEnum = iota
    MyEnumTwo
    MyEnumThree
)

In Javascript, you can then use the following:

const MyEnum = {
  MyEnumOne: 0,
  MyEnumTwo: 1,
  MyEnumThree: 2,
};

• Why use float64? Can't we use int?
  • Because JavaScript doesn't have a concept of int. Everything is a number, which translates to float64 in Go. There are also restrictions on casting types in Go's reflection package, which means using int doesn't work.