When to use Type Aliases and Type Definitions in GO?

When to use Type Aliases?

Use Type Aliases only during code base refactoring to move types between packages. Codebase Refactoring (with help from Go)

When to use Type Declaration?

Use Type Declaration to create enums and to add extra behaviour to basic types.

1. Constants using iota

Create new type with limited value range. It makes code more readable and safe:

type Vehicle int

const (
    Bike Vehicle = iota
    Scooter
    Car
    Bus
    Train
)

2. Extra behaviour

Create new type to add extra behaviour. I would always question the need for this.

type Person string

func (p Person) Hello(anotherPerson Person) {
    fmt.Printf("%s, Hello from %s", anotherPerson, p)
}

elon := Person("Elon Musk")
aleh := Person("Aleh")

elon.Hello(aleh) // Aleh, Hello from Elon Musk