You can use the sort() method of Array, which takes a callback function, which takes as parameters 2 objects contained in the array (which we call a and b)

listOfHouses.sort((a, b) => (a.value > b.value) ? 1 : -1)

Loop starts after sorting

You need to send sort object in your express Request , but you have some errors in your code :

• to get a value from DOM select element you need to add id to the select element not to option. for example :

<select id="sorting" class="form-select" aria-label="Default select example">
  <option selected>Sort by</option>
  <option value="1">Low to High price</option>
  <option value="2">High to low price</option>
  <option value="3">From A to Z</option>
  <option value="4">From Z to A</option>
</select>

To get the selected value you can do it by your function in this mode :

function getSortingObject() {


    const value = document.getElementById("sorting").value

    if (document.getElementById("sorting").value === "1") {
        return {price:1}
    } else if (document.getElementById('sorting').value == "2") {
        return {price:-1}
    } else if (document.getElementById('sorting').value == "3") {
        return "title: 1"
    } else if (document.getElementById('sorting').value == "4") {
        return {title:1}
    } else {
        return {title:-1}
    }
}

Now you need to send the current sorting object from your front-end to your backend so you need to get the sorting object in this mode :

const sortingObject = getSortingObject()

fetch(YOUR URL,YOUR_BODY WITH Sorting object )

In the backend you need to validate thet the sorting object is allowed to be used ar coded the allowed pros to sort in this mode :

 module.exports.listOfHouses = async (req, res) => {
    const canSortBy = ["title","price"]
    const sortingoBJECT = req.body.sortingObject
 
    const canSort = Object.keys(sortingoBJECT).findIndex(r=>!canSortBy[r])
    if(canSort) res.sendStatus(....)




     const houses = await House.find({}).sort(sortingoBJECT);
     res.render('houses/houses', {
         houses
     });
 };