What will happen when control flow changes when a variable is init?

[Jack-Works]

function x(obj) {
    obj.y = () => y
    const y = do {
        if (true) return 0
        1
    }
}

const y = {}
x(y) // 0
x.y() // ?

[bakkot]

It would throw, because y has not been initialized.

[Jack-Works]

Thanks. cc @kingwl

[Kingwl]

because y has not been initialized.

Is that means the expression of return statement will be ignored?

Sorry I have some misunderstanding. It's might related/duplicated with #30