obj.constructor.name polyfill

get-class-name.js

  const getClassName = function(obj) {
    if (obj.constructor.name) return obj.constructor.name;

    // Chrome "function HTMLButtonElement() { [native code] }"
    var funcMatch = obj.constructor.toString().match(/^\s*function\s*(\S+)\s*\(/);
    // IE11   "[object HTMLButtonElement]"
    var objMatch = obj.constructor.toString().match(/\[object\s(\S+)\]/);
 
    return objMatch ? objMatch[1] : funcMatch[1];
  }