Adding functionality to Intl.NumberFormat

Question

I'm trying to add functionality to the format function but there is something wrong with my code:

Object.defineProperty(Intl.NumberFormat.prototype, "format", { value: function(){
     //your logic here
     let orig = Intl.NumberFormat.prototype
     console.log(orig);// does not remember the original proto
}, configurable: true } );

What am I missing?

Answer 1

You basically catch the property itself. You want to get the original one so before it is overriden, and you may store its subobject references too through copying them:

{
   let orig = Object.assign({}, Intl.NumberFormat.prototype);
   Object.defineProperty(Intl.NumberFormat.prototype, "format", { value: function(){
      //your logic here     
     console.log(orig);// does remember the original proto
   }, configurable: true } );
}