35. Type Aliases

A Type Alias is used to create a new name for a type. Type aliases can be used to create a shorthand for complex types or define a union type.

Example:

type Name = string;
type NameResolver = () => string;
type NameOrResolver = Name | NameResolver;
 
function getName(n: NameOrResolver): Name {
  if (typeof n === "string") {
    return n;
  } else {
    return n();
  }
}
 
const name = getName("John Doe");
const resolvedName = getName(() => "Jane Doe");

Here:

• Name is a type alias for string.
• NameResolver is a type alias for a function that returns a string.
• NameOrResolver is a union type alias, combining Name and NameResolver.