javascript

CHAPTER 5 ■ MEMBER INHERITANCE
var MintChocolateChunk = function(mint) {
this.mint = mint || [1, "cup", "fresh mint leaves"];
};
MintChocolateChunk.prototype = new Chocolate();
Now let’s add a vanilla member to override Chocolate.prototype.vanilla. Insofar as we’re
chipping the Callebaut bittersweet chocolate, we need only 1 cup, rather than 1 1/2 cups. So, let’s modify
the first element in the MintChocolateChunk.prototype.bittersweet array. Finally, we don’t want the
cocoa, so pass that member to the delete operator, which we covered in Chapter 3.
var VanillaBean = function(vanilla, cinnamon) {
this.vanilla = [1, "bean", vanilla ? vanilla : "Madagascar Bourbon"];
cinnamon && (this.cinnamon = [1, "stick", "Saigon"]);
};
VanillaBean.prototype = {
heavyCream: [1, "cup", "Organic Valley"],
halfHalf: [2, "cup", "Organic Valley"],
sugar: [5/8, "cup"],
yolks: [6]
};
var Coffee = function(coffee) {
this.coffee = coffee || [1/4, "cup, coarsely ground", "Starbucks Espresso"];
};
Coffee.prototype = new VanillaBean();
var Chocolate = function(cocoa, bittersweet) {
this.cocoa = cocoa || [3/16, "cup", "Callebaut"];
this.bittersweet = bittersweet || [1 + 1/2, "cup", "Callebaut"];
};
Chocolate.prototype = new VanillaBean();
Chocolate.prototype.yolks = [4];
var MintChocolateChunk = function(mint) {
this.mint = mint || [1, "cup", "fresh mint leaves"];
};
MintChocolateChunk.prototype = new Chocolate();
MintChocolateChunk.prototype.vanilla = [1/3, "bean", "Madagascar Bourbon"];
MintChocolateChunk.prototype.bittersweet[0] = 1;
delete MintChocolateChunk.prototype.cocoa;
Having done so, let’s create a MintChocolateChunk() instance named mintChocolateChunk, verifying
our work with Figure 5–7. Note that mintChocolateChunk has its own mint member and inherits other
members from MintChocolateChunk.prototype, Chocolate.prototype, and VanillaBean.prototype.
var VanillaBean = function(vanilla, cinnamon) {
this.vanilla = [1, "bean", vanilla ? vanilla : "Madagascar Bourbon"];
cinnamon && (this.cinnamon = [1, "stick", "Saigon"]);
};
VanillaBean.prototype = {
heavyCream: [1, "cup", "Organic Valley"],
halfHalf: [2, "cup", "Organic Valley"],
sugar: [5/8, "cup"],
yolks: [6]
};
var Coffee = function(coffee) {
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