How do I add a getter method to the built in String object?

Question

I trying to add a getter method to String so that it can be called like so:

'make me bold'.bold

Without parentheses. Here is how I'm trying to define the function, as described here .

String.prototype.defineProperty(window, 'bold', { get: function (input) {
  return ('</b>'+input+'</b>');
}});

It says that defineProperty isn't a function though. Doesn't work if i take out prototype either. It looks possible to do with 'String.prototype. defineGetter ' but says it's deprecated:

String.prototype.__defineGetter__('bold', function (input) {
  return ('</b>'+this+'</b>');
});

Answer 1

You need to use Object.defineProperty:

Object.defineProperty(String.prototype, 'bold', { get: function (input) {
  return ('</b>'+this+'</b>');
}});

Answer 2

You can add that function to the prototype instead:

 String.prototype.bold = function () { return ('</b>' + this + '</b>'); }; console.log('make me bold'.bold()) console.log('Ele from SO'.bold())