javascript

CHAPTER 5 ■ MEMBER INHERITANCE
Now then, Object.create() will take an optional second parameter when it eventually arrives,
which is an object containing members to add to the clone. So, let’s define a second function named
emulate() that does the same thing while we wait for better days:
var emulate = function (donor, more) {
var Proxy = function () {}, child, m;
Proxy.prototype = donor;
child = new Proxy();
for (var m in more) {
child[m] = more[m];
}
return child;
};
Now say we’ve made a quart of chocolate ice cream and want to make a quart of Ben & Jerry’s New
York Super Fudge Chunk. We can do so by passing the chocolate quart plus the additional ingredients to
emulate(). Try it, verifying your work with Figure 5–18:
var emulate = function (donor, more) {
var Proxy = function () {}, child, m;
Proxy.prototype = donor;
child = new Proxy();
for (var m in more) {
child[m] = more[m];
}
return child;
};
var chocolate = {
heavyCream: [1, "cup", "Organic Valley"],
halfHalf: [2, "cup", "Organic Valley"],
sugar: [5/8, "cup"],
yolks: [6],
cocoa: [3/8, "cup", "Callebaut, Dutch process"],
vanilla: [1, "bean", "Madagascar Bourbon"]
};
var newYorkSuperFudgeChunk = emulate(chocolate, {
pecans: [1/4, "cup, coarsely chopped"],
walnuts: [1/4, "cup, coarsely chopped"],
almonds: [1/4, "cup, coarsely chopped"],
whiteChocolate: [1/3, "cup, coarsely chopped", "Callebaut"],
bittersweetChocolate: [1/3, "cup, coarsely chopped", "Callebaut"]
});
console.dir(chocolate);
console.dir(newYorkSuperFudgeChunk);
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