JSFiddle - React, Tailwind, and code Playground

HTML

<input type=text id=textinput>
<button id=button>test</button>

JavaScript

$(function(){
  $("#button").click(function() {
  		var val = $("#textinput").val();
      console.log(isStringNumber(val));
      function isStringNumber(str) {
        var parsed = parseFloat(str);
        var casted = +str;
        return parsed === casted  && !isNaN(parsed) && !isNaN(casted);
    }
  })
});