void type

Learn functions that do not return a value with void.

The void type

The void type is the return type of functions that do not return a value. If a function performs an action but produces no result, its return type is void. A void function ends normally, meaning unlike never, the function does finish.

function selam(): void {
  console.log("Merhaba");
}

void indicates that a function does something but returns no value.

void vs never

The difference between void and never: a void function ends normally but yields no value; a never function never ends. You can write return; in a void function, but return is unreachable in a never function.

function bitir(): void { return; }
function patla(): never { throw new Error(); }

void means normal completion; never means no completion.

Exercise Write a void function

Define a function named selamVer with an isim parameter of type string and return type void. The function should concatenate "Merhaba, " with isim and print it with console.log. Call the function with "Dünya".

Show example solution

function selamVer(isim: string): void {
    console.log("Merhaba, " + isim);
}
selamVer("Dünya");

Test yourself

What does the <code>void</code> return type indicate?
- The function never completes
- The function returns no value
- The function throws an error
- The function returns any type
Show answer

The function returns no value — <code>void</code> indicates that the function ends normally but returns no value; <code>never</code> means the function never finishes at all.

Add the void return type

function logla(mesaj: string): ____ { console.log(mesaj); }

Show answer

function logla(mesaj: string): void { console.log(mesaj); }

void concepts

void

Function returning no value
function f(): void { }

Completes normally, no value
void vs never

void ends normally, never does not
return;

Return without a value

Next lesson: Summary - Special types

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