It appears that the void type can sometimes replace the return type when employed as an interface within TypeScript

interface Check {
name: string;
_meth(): void;
}

class ClassDemo implements Check {
name: string = 'something';
_meth() {
return 'string';
}

}

Upon examining the interface, it is evident that the return type for _meth should be void. However, TypeScript is not flagging an error for the class implementation; instead, it is applying type inference. While void typically signifies a return of "void," this behavior is still new to me as a TypeScript learner. I would greatly appreciate an explanation for this discrepancy.

Answer №1

In my opinion, the compatibility issue is mainly a matter of convenience. I do see the point that when it comes to implementing an interface, it may not always be as logical.

Let's take a look at a scenario where a function accepts a Check interface:

export function f(check: Check): void
{
    const s = check._meth();
    console.log(s.slice(0,1)); // compile error
}

If you're unable to access the return value, it's almost as if it doesn't even exist :)

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