How to get a constructor function to inherit from a constructor function in Javascript?

Question

So I\'m learning Javascript and all its\' prototype goodness, and I am stumped over the following:

Say I have this

var Animal = function (a, b, c, d,         


        

Answer 1

It quickly becomes tedious to remember the order and meaning of long lists of parameters like this.

You can add some flexibility if you pass the properties of a new Animal as an object- and it is not so hard to remember as a long list of argument indexes.

function Animal(features){
 for(var p in features){
  this[p]= features[p];
 }
};

You can give every cat some basic cat features automatically, 
and add specifics when you make a new cat.

function Cat(features){
 for(var p in features){
  this[p]= features[p];
 }
}
Cat.prototype= new Animal({legs: 4, eats: 'meat', type: 'mammal', whiskers: true});
Cat.prototype.constructor=Cat;

var Tiger= new Cat({tail: true, hunter: true});
Tiger begins with these properties:

tail: true
hunter: true
legs: 4
eats: meat
type: mammal
whiskers: true