JSFiddle - React, Tailwind, and code Playground

JavaScript

var data = {
    "Menu1": "Item1",
    "Menu2": {
        "SubMenu1": "SubItem1",
        "SubMenu2": "SubItem2"
    },
    "Menu3": "Item3",
    "Menu4": {
        "SubMenu2": {
            "SubSubMenu1": "SubSubItem1"
        }
    }
};

function makeMenu(data) {
    var html = "<ul>";
    $.each(data,function(key,val){
        html += "\n<li>";
        if (typeof val === "object")
           html +=  key +"\n" + makeMenu(val);
        else
           html += val;
        html += "\n</li>";
    });
    html += "\n</ul>";
    return html;
};

var menu = makeMenu(data);
$(menu).appendTo("body");
alert(menu);