#Inheritance Styles
Here are a few different ways to try and implement prototypal inheritance in a classical way. In these examples, we try to derive a more specific class of the base class - Asset.
By inspecting the web development tools console output in Chrome you can see the prototype chain and view the differences of each approach.
<html>
<body>
<script>
var __extends = this.__extends || function (d, b) {
function __() { this.constructor = d; }
__.prototype = b.prototype;
d.prototype = new __();
};
var Asset = (function() {
function Asset(lat, lon) {
this.lat = lat;
this.lon = lon;
}
return Asset;
})();
var MoonRock = (function(_super) {
__extends(MoonRock, _super);
function MoonRock(lat, lon, desc) {
_super.call(this, lat, lon);
this.desc = desc;
}
return MoonRock;
})(Asset);
function POI(lat, lon, desc) {
this.desc = desc;
}
POI.prototype = new Asset("lat", "lon");
POI.prototype.constructor = POI;
var poi = new POI("a", "b", "desc");
/* Car Door */
function newCarDoor(lat, lon, desc) {
var instance = Object.create(new Asset(lat, lon));
instance.desc = desc;
return instance;
};
var asset = new Asset(123, 456);
var poi = new POI("abc", "def", "description");
//var carDoor = new newCarDoor("abc", "def", "description");
var carDoor = newCarDoor("abc", "def", "description");
var moonRock = new MoonRock("abc", "def", "description");
console.log("asset: %o", asset);
console.log("instanceOf(Asset) " + (asset instanceof Asset));
console.log("");
console.log("poi: %o", poi);
console.log("instanceOf(POI) " + (poi instanceof POI));
console.log("");
console.log("carDoor: %o", carDoor);
console.log("instanceOf(CarDoor) " + (carDoor instanceof newCarDoor));
console.log("");
console.log("moonRock: %o", moonRock);
console.log("instanceOf(MoonRock) " + (moonRock instanceof MoonRock));
</script>
</body>
</html>And here is the relevant output:
asset: Asset
lat: 123
lon: 456
__proto__: Asset
constructor: function Asset(lat, lon) {
__proto__: Object
instanceOf(Asset) true
poi: POI
desc: "description"
__proto__: Asset
constructor: function POI(lat, lon, desc) {
lat: "lat"
lon: "lon"
__proto__: Asset
constructor: function Asset(lat, lon) {
__proto__: Object
instanceOf(POI) true test.htm:60
carDoor: Asset
desc: "description"
__proto__: Asset
lat: "abc"
lon: "def"
__proto__: Asset
instanceOf(CarDoor) false test.htm:64
moonRock: MoonRock
desc: "description"
lat: "abc"
lon: "def"
__proto__: __
constructor: function MoonRock(lat, lon, desc) {
__proto__: Asset
constructor: function Asset(lat, lon) {
__proto__: Object
instanceOf(MoonRock) true