Enum equal for object prototype usable in Typescript

Object.prototype.enumEqual.js

var States;
(function (States) {
    States[States["New"] = 1] = "New";
    States[States["Active"] = 2] = "Active";
    States[States["Disabled"] = 3] = "Disabled";
})(States || (States = {}));

Object.prototype.enumEqual = function(enumType, enumItem) {
  debugger;
  var isNum = function(v) { return !isNaN(parseInt(v)); };
  var enumValueToCompare = enumItem;

  var thisIsNumber = isNum(this);
  
  if (thisIsNumber)
  {
    if (!isNum(enumItem)) // enumItem is NOT number
      enumValueToCompare = enumType[enumItem];
  }
  else{ // this is NOT number
    if (isNum(enumItem)) { // enumItem IS number
       var enumMember = enumType[enumItem];
       if (!isNum(enumMember)) // enumMember is NOT number
           enumValueToCompare = enumMember;
    }
    else {
      // do nothing (same as default: enumValueToCompare = enumItem)
    }
  }
           
  return this == enumValueToCompare;
};

var result = '';
result += "Active".enumEqual(States, States[States.Active]) + ' | ';
result += "Active".enumEqual(States, States.Active) + ' | ';
result += "Active".enumEqual(States, 2) + ' | ';
result += "Active".enumEqual(States, "Active") + ' | ';

result += States.Active.enumEqual(States, "Active") + ' | ';

var num = 2;
result += num.enumEqual(States, States[States.Active]) + ' | ';
result += num.enumEqual(States, States.Active) + ' | ';
result += num.enumEqual(States, 2) + ' | ';
result += num.enumEqual(States, "Active") + ' | ';

alert(result);