JSFiddle - React, Tailwind, and code Playground

HTML

<div id="output">
</div>

JavaScript

function isInt(a){
	return !isNaN(a) && parseInt(a) == parseFloat(a);
}

$('#output').append("1 " + isInt(1) + "</br>");
$('#output').append("1.0 " + isInt(1.0) + "</br>");
$('#output').append("\"1\" " + isInt("1") + "</br>");
$('#output').append("\"1.0\" " + isInt("1.0") + "</br>");
$('#output').append("\"\"" + isInt("") + "</br>");
$('#output').append("\" \"" + isInt(" ") + "</br>");
$('#output').append("\"a\"" + isInt("a") + "</br>");
$('#output').append("\"1a\"" + isInt("1a") + "</br>");
$('#output').append("1.5 " + isInt(1.5) + "</br>");
$('#output').append("\"1.5\" " + isInt("1.5") + "</br>");
$('#output').append("null " + isInt(null) + "</br>");