How to use void and number type in functions with guard-clauses-CodePudding

Problem: I'm trying to write a simple function with a guard-clause in addition to returning a value with type: number, but ESLint is telling me "void is only valid as a return type or generic type variable"

P.S: I don't know why ESLint is throwing me this, if I use void as a return type for guard-clause ...

Code:

function addTwoNumbers(one: number, two: number): void | number {
  if (one < 0 || two < 0) return;
  return one   two;
}

const result = addTwoNumbers(-5, -5);
console.log(result);

I've tried specifying only number type to the function, but in this case ESLint is telling me "Type undefined is not assignable to type number"

CodePudding user response：

Instead of void you need to put undefined. By default, an empty return statement will return undefined.