JS Bus Schedule

function solve() {
    let infoSpan = $("#info span");
    let departButton = $("#depart");
    let arriveButton = $("#arrive");
    let nextId = "depot";
    let nextStop = "";

    function update() {
    let link = "https://judgetests.firebaseio.com/schedule/" + nextId + ".json";
    $.ajax({
        url: link,
        method: "GET",
        success: updateDepartStop,
        error: drawError
    });

    function updateDepartStop(obj) {
        nextStop = obj.name;
        nextId = obj.next;
        infoSpan.text("Next stop " + nextStop);
    }

    function drawError() {
        infoSpan.text("Error");
        departButton.prop("disabled", true);
        arriveButton.prop("disabled", true);
    }
    }

    function depart() {
    departButton.prop("disabled", true);
    arriveButton.prop("disabled", false);
    update();
    }

    function arrive() {
    arriveButton.prop("disabled", true);
    departButton.prop("disabled", false);
    infoSpan.text("Arriving at " + nextStop);
    }

    return {
    depart,
    arrive
    };
}