JSFiddle - React, Tailwind, and code Playground

HTML

<ul id="items">
   <li id="item_1_dish">Item 1</li>
   <li id="item_2_dish">Item 2</li>
   <li id="item_3_dish">Item 3</li>
</ul>
<button onclick="getNum">adsf</button>

JavaScript

function getNum(element, attrPrefix){
    var prefix = attrPrefix;
    var num = parseInt(element.attr("items").substring((prefix.length)));
     getNum($(field), "item_");
}
function updateDish(field) {
      var num = getNum($(field), "item_");
     //Rest of function ...
     console.log("Number = " + num);// 1_dish, 2_dish, 3_dish
}
updateDish("#item_1_dish");