Swift - Data Type Type Alias

  1. HOME
  2. Swift
  3. Data Type
  4. Type Alias

Introduction

A type alias defines an alternative name for the existing data type.

For example, using the built-in types you can specify the data type for variables like this: 

var customerID : UInt32
var customerName: String

However, it would be more useful if you could provide a more meaningful and contextually relevant name using the typealias keyword: 

typealias  CustomerIDType = UInt32
typealias  CustomerNameType = String

Here, CustomerIDType is the alias for the UInt32 type, and CustomerNameType is the alias for the String type.

You can use the aliases as if they are the data types, like this:

Demo

typealias  CustomerIDType = UInt32
typealias  CustomerNameType = String

var customerID :  CustomerIDType
var customerName:  CustomerNameType

customerID = 12345//from  w ww . j  a v a  2 s.c  o  m
customerName = "Json"

print(customerName);

Result