In Scala, aliases are used to give a short name to a long type. This helps in simplifying the code by making it more readable. We can use the alias keyword to create a type alias in Scala.
For instance, consider the following example:
type EmployeeID = String
val empId: EmployeeID = "12345"
In the above example, we have created a type alias called EmployeeID, which is an alias for the String type. We have then assigned a value to the empId variable of type EmployeeID.
Another example of using an alias could be when we have to define commonly used types such as lists, maps, etc.
type IntList = List[Int]
val numbers: IntList = List(1, 2, 3, 4, 5)
Here, we have defined an alias IntList, which is an alias for the List[Int] type. We have then created a variable numbers of type IntList and assigned it a List of Integers.
We can also define aliases for complex types such as functions.
type F = Int => Int
val f: F = x => x * x
In this example, we have created an alias F for the function type Int => Int. We have then assigned a function to the variable f of type F.
In summary, aliases in Scala are a way to give a short name to a long type, and can be used to simplify code and make it more readable.