How to get key from destructed object sweetalert2

Below code pops up a modal in the view that user select one of the options and then shows the selected option, I also need the id of selected option. e.g I need to get “4” if user select “John”. I am not sure how can I get it

        async function accept() {
            const { value: student } = await Swal.fire({
                input: 'select',
                width: 260,
                inputOptions: {
                    1: 'Peter',
                    2: 'Sam',
                    3: 'Tom',
                    4: 'John'
                },
                inputPlaceholder: 'Select student',
                showCancelButton: true,
            })
            if (student) {
                Swal.fire(`You selected: ${student}`)
                console.log('Id: ' ?????)
            }
        }