Javascript儿童的构造函数名称

Question

Question

How one could retrieve the children' (of any inheritance depth level) constructor name?

Explanation

Let us have class Cat that extends the Model class. And the class Kitten that extends the Cat class.

What I want is printed to the console (for example) string "Kitten" when one creates the Kitten class instance and the string "Cat" when one creates the Cat class instance.

The trick is that the code that outputs the constructor name should be located at the base ( Model for the example shown) class.

Note: I'm good at Ruby, compared (in the scope of myself) to Javascript. So the "pseudo-code" shall be the Ruby-ish one =)

# pseudo-Ruby-code
class Model
  def initialize
    console.log(self.constructor.toString())
  end
end

class Cat << Model
  # something goes here
end

class Kitten << Cat
  # and here too
end

# shows "Model"
Model.new

# shows "Kitten"
Kitten.new

# shows "Cat"
Cat.new

Answer 1

This is how I would do it using Coffee-Script.

class Model

    constructor: (animal = "Model") ->

        console.log animal;



class Cat extends Model

    constructor: (animal = "Cat") ->

        super animal


class Kitten extends Cat

    constructor: (animal = "Kitten") ->

        super animal

new Kitten()

// => Kitten

This is the compiled JavaScript:

var Cat, Kitten, Model,
  __hasProp = {}.hasOwnProperty,
  __extends = function(child, parent) { for (var key in parent) { if (__hasProp.call(parent, key)) child[key] = parent[key]; } function ctor() { this.constructor = child; } ctor.prototype = parent.prototype; child.prototype = new ctor(); child.__super__ = parent.prototype; return child; };

Model = (function() {

  function Model(animal) {
    if (animal == null) {
      animal = "Model";
    }
    console.log(animal);
  }

  return Model;

})();

Cat = (function(_super) {

  __extends(Cat, _super);

  function Cat(animal) {
    if (animal == null) {
      animal = "Cat";
    }
    Cat.__super__.constructor.call(this, animal);
  }

  return Cat;

})(Model);

Kitten = (function(_super) {

  __extends(Kitten, _super);

  function Kitten(animal) {
    if (animal == null) {
      animal = "Kitten";
    }
    Kitten.__super__.constructor.call(this, animal);
  }

  return Kitten;

})(Cat);

new Kitten();

You can try it yourself here