Is a number of type never?

A small snippet of code is breaking my head:

   var label: number= 12354;
   if(typeof(label) == 'number'){
      label =label.toString();
   }

But it’s giving an error in toString: The property ‘toString’ does not exist in type ‘never’. But it is a number! Why does inside if say it is of type never? If you change label to type any, the errors will be eliminated. I want to know why typescript ignored validation and stated something impossible in the presented context?

    //Expectation
    label = '12345';
    //Reality:
     Property 'toString' does not exist in type 'never'.ts(2339)

>Solution :

Try this way

var label: number | string = 12354;

if (typeof label === 'number') {
  label = label.toString();