Function Alias in TypeScript

In TypeScript, an alias is a custom type which represents an existing type in the code in a more readable and concise form. It helps to reduce code duplication and improve code readability.

To create an alias in TypeScript, we use the type keyword followed by the alias name, an equal sign (=), and the type we want to alias. Here is an example:

type Age = number;
type Person = {
  name: string;
  age: Age;
};

In this example, we have defined two aliases Age and Person. Age is an alias for the number type and Person is an alias for an object type with two properties: name of string type and age of Age type (which itself is an alias for number).

We can then use these aliases to define function parameters, interfaces, classes, and other types in our TypeScript code:

function printPerson(person: Person) {
  console.log(Name: ${person.name}, Age: ${person.age});
}
const john: Person = { name: 'John', age: 25 };

printPerson(john);

Here, we have defined a printPerson function which takes a Person object as a parameter. We have also defined a john object which is of type Person and passed it as an argument to the printPerson function.

Using aliases in TypeScript makes our code more readable and easier to maintain. It provides a way to create expressive and self-documenting code.