JSFiddle - React, Tailwind, and code Playground

HTML

<input type="number" id="id_2" value="0">
<input type="number" id="id_3" value="0">
<input type="number" id="id_1" value="0">

JavaScript

var shoppingCart = new Array();
shoppingCart[0] = "prod_1";
shoppingCart[1] = "prod_3";
shoppingCart[2] = "prod_2";

for(var i = 0; i < shoppingCart.length; i++) {
    var val = shoppingCart[i];
    
    $("#id" + val.substring(4)).val( "5");
}