JSFiddle - React, Tailwind, and code Playground
HTML
<script src="https://cdnjs.cloudflare.com/ajax/libs/underscore.js/1.8.3/underscore-min.js"></script>
<script src="//code.jquery.com/jquery-1.11.3.min.js"></script>JavaScript
var ab = {};
ab[22] = { "a": 1, "b":2 }
ab[23] = { "a": 2, "b":2 }
console.log(ab);
var t = ab[23];
console.log(t !== void 0);
delete ab[22];
console.log(ab);