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JavaScript Objects
Classless creation
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Create data object using constructor
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function Person(id,age)
{
this.id=id;
this.age=age;
}
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o=new Person("bob",60);
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id=bob age=60
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Create data object directly
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n/a
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o = new Object();
o.id="bob";
o.age=60;
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id=bob age=60
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Create data object directly [alternative]
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n/a
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o={id:"bob",age:60};
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id=bob age=60
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Create behavioural object using constructor
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function Person(id,age)
{
this.id=id;
this.age=age;
this.makeOlder=makeOlder
function makeOlder()
{
// always need "this" prefix
this.age++;
}
}
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o=new Person("bob",60);
o.makeOlder();
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id=bob age=61
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Classless inheritance
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Classless single inheritance
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function Rect(h,w) // superclass
{
this.h=h; // height
this.w=w; // width
this.x=0; // x pos
this.y=0; // y pos
this.move = function move(x,y)
{
this.x+=x;
this.y+=y;
}
}
function Square(w,a) // subclass
{
Rect.call(this,w,w);
this.angle=a;
}
Square.prototype = Object.create(Rect.prototype);
Square.prototype.constructor = Square;
o = new Square(10,45);
o.move(1,1);
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t =
(
o instanceof Square &&
o instanceof Rect &&
o.x==1 &&
o.y==1 &&
o.h==10 &&
o.w==10 &&
o.angle==45
)
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true
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Version: JavaScript-C24.8.1
Description: Debian GNU/Linux 8.2 (jessie)
Release: 8.2
Codename: jessie
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