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>');
});

score 2 · Accepted Answer · answered Mar 03 '18 at 17:38

2

You need to use Object.defineProperty:

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

answered Mar 03 '18 at 17:38

Axnyff

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I get it now. Thought object was a placeholder. – stackers Mar 03 '18 at 17:53

score 0 · Answer 2 · answered Mar 03 '18 at 17:36

0

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())

answered Mar 03 '18 at 17:36

Ele

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I think he means to call it without parentheses – baao Mar 03 '18 at 17:40
@baao yes, but this is an alternative. I mean, can help anyone else. – Ele Mar 03 '18 at 17:42
I think it even makes more sense... :-) – baao Mar 03 '18 at 17:46

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

2 Answers2