Exploring the Difference Between Type Alias and Named Type (Golang)
October 13, 2023
Both are methods of redefining existing types when defining a new type, and are defined as follows:
type MyStruct struct {
Name string
Age int
}
func(m MyStruct) Print(){
fmt.Println(m.Name, m.Age)
}
type MyStructNamed MyStruct // Named Type
type MyStructAlias = MyStruct // Type AliasType Alias
In the case of a type alias, it assigns an alias to the existing type, so it has the same methods as the existing type.
package main
func main() {
var m MyStructAlias
m.Name = "GiraffeWithCode"
m.Age = 27
m.Print()
// GiraffeWithCode 27
}Named Type
A Named Type does not have the same methods as the existing type.
package main
func main() {
var m MyStructNamed
m.Name = "GiraffeWithCode"
m.Age = 27
m.Print() // Error occurs
// ./main.go:18:3: m.Print undefined (type MyStructNamed has no field or method Print)
}Therefore, explicit type casting is necessary.
package main
func main() {
var m MyStructNamed
m.Name = "GiraffeWithCode"
m.Age = 27
m.(MyStruct).Print()
// GiraffeWithCode 27
}When to Use?
- If you want to define a new type and clarify the relationship between types, it is better to use Named Type.
- If you want to improve the readability of the code by giving another name to an existing type, you can use a Type Alias.