Question

Is it possible to set something of a default/fallback function for a JavaScript class?

var a = new function() {

  this.b = function() {
    return "B";
  }

  return "A";
}

In this example, I’d want to see B when executing alert(a.b()), and A for alert(a) alone.

Answer 1

var a = new function() {    
  this.toString = function() { return "Four Loko comes in 8 different flavors."; };
  this.valueOf = function() { return "Four Loko comes in 8 different flavors."; };
  this.b = function() { return "Added! :3"; };
}
alert(a);
alert(a.b());

If you overwrite the toString method of an object you can get it to return whatever you want.

Although you may be trying to return literal values from a constructor. You can only return objects from a constructor.

You may also want to overwrite .valueOf