JuniorTheoryCommon

On which line does tsc report an error?

TypeScript

function show(id: string | number) {
    console.log(id.toString());
    console.log(id.length);
}

show(42);

Expecting no error because id is sometimes a string: TypeScript allows only what both string and number have, and a number has no length.
Expecting an error on line 2 as well: toString exists on both strings and numbers, so calling it on string | number is allowed.

JuniorTheoryCommon

TypeScript

function show(id: string | number) {
    console.log(id.toString());
    console.log(id.length);
}

show(42);

Expecting no error because id is sometimes a string: TypeScript allows only what both string and number have, and a number has no length.
Expecting an error on line 2 as well: toString exists on both strings and numbers, so calling it on string | number is allowed.