function arrayToList(array) {
    let list = null;
    for (let i = array.length - 1; i >= 0; i--) {
        list = {
            value: array[i],
            rest: list
        };
    }
    return list;
}

console.log('arrayToList: ', arrayToList([10, 20]));

const list = { value: 10, rest: { value: 20, rest: null } };

function prepend(newElement, list){
    return {
        value: newElement,
        rest: list
    }
}

console.log('prepend: ', prepend(5, list));

function nth(position, list){
    let place = 0;
    while(list.rest){
        if(place === position){
            return list.value;
        }
        list = list.rest;
        place++;
    }
    if(place === position){
        return list.value;
    }
}

console.log('nth: ', nth(1, list))

function listToArray(list){
    let array = [];
    while(list.rest){
        array.push(list.value);
        list = list.rest;
    }
    array.push(list.value);
    return array;
}

console.log('listToArray: ', listToArray(list));