The Role of Void Type in TypeScript

If you have been using TypeScript, you probably already heard about void type.

It might seem a simple concept at first, but it plays a significant role in TypeScript development, especially in the context of functions.

In this article, we will talk about the void type and its use cases.

What is the Void Type?

The void type in TypeScript represents the absence of a value or a return type.

It is commonly used in functions that do not return any value:

As you probably already know, in JavaScript, functions automatically return undefined when they lack a return statement.

But in TypeScript, functions as such are marked as void return type.

Void in Variable Declarations

In theory, void type can also be used when declaring variables to indicate that a variable will not hold any value:

But it’s not commonly applied practice, because it’s not as practical as to use it in functions.

Void in Callbacks

Void is very useful in callbacks and functions passed as arguments where you do not care about the return value:

Some Tips

• Mark functions that do not return a value with void type. It helps with readability, clarity, and function intention.

• Try to avoid using void type in variable declarations. Mostly it brings no benefits because it holds no information about variable purpose or use.

• When you are defining callbacks and functions as arguments, use void to indicate that the return value will be ignored. It helps to promote flexibility in callback implementations.