How to get a constructor function to inherit from a constructor function in Javascript?
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, e, f, g, h, i, j, k , l, m, n){
this.a = a;
this.b = b;
//...etc...
};
var x = new Animal(1,2,3....);
Now how do I create a Cat constructor function that inherits from the Animal constructor function such that I don't have to type the super long arguments again?
In other words I don't want to be doing this:
var Cat = function (a, b, c, d, e, f, g, h, i, j, k , l, m, n){
this.a = a;
this开发者_开发问答.b = b;
//...etc...
};
// inherit functions if any
Cat.prototype = new Animal;
var y = new Cat(1,2,3....);
Thanks in advance! j
How's this?
var Cat = Function (a, b, c, d, e, f, g, h, i, j, k , l, m, n){
Animal.apply(this, arguments);
};
// inherit functions if any
Cat.prototype = new Animal;
var y = new Cat(1,2,3....);
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
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