In this tutorial, you will learn how to define new names for types using type aliases.
Introduction to TypeScript type aliases
Type aliases allow you to create a new name for an existing type. The following shows the syntax of the type alias:
type alias = existingType;
The existing type can be any valid TypeScript type.
The following example use the type alias chars for the string type:
type chars = string;
let messsage: chars; // same as string type
It’s useful to create type aliases for union types. For example:
type alphanumeric = string | number;
let input: alphanumeric;
input = 100; // valid
input = 'Hi'; // valid
input = false; // Compiler error
Conclusion
Use type aliases to define new names for existing types.
