Store ALL user input onto Local-Storage

Im currently working with forms and saving the data on Local Storage.

my form is ->

<form id="formy">
<input class="add" id="num1">
<select class="add" id"num2">
 <option value="act1"> Try </option>
 <option value="act2"> Try2 </option>
<input class="add" id="num3">
<input class="add" id="num4">
</form>

I have 3 inputs and 1 select, I'm able to store the first input, i would like to store in the array ["Hi", "Try2", "LoveCode", "LY"]

But I only get ["Hi"] the first input stored only.

heres js code

const myForm = document.getElementById("formy");

    myForm.addEventListener("submit", addTodo);


function addTodo(e) {
        e.preventDefault();
        const userInput = document.querySelector("add").value;
        const userListItem = document.createElement("li");
        userListItem.appendChild(document.createTextNode(userInput));
        list.appendChild(userListItem);
        const myArray = map(listItems, getText);
        localStorage.setItem('titols', JSON.stringify(myArray));
    }

    const listItems = document.getElementsByTagName('li');


    function map(arrayLike, fn) {
        var ret = [], i = -1, len = arrayLike.length;
        while (++i < len) ret[i] = fn(arrayLike[i]);
        return ret;
    }