Question

Im probably missing the point totally here so apologies. But Im wondering what the difference between using ‘this’ and ‘prototype’ are in this context. And what I should really be using to construct rich classes that are reusable…

I have this…

function MyClass() {

}

MyClass.prototype.name = null;

MyClass.prototype.init = function () {

    console.log('init');

    MyClass.prototype.name = 'Peter set by proto';

    this.name = 'Peter set by this';

};

MyClass.prototype.SayName = function() {

    console.log(MyClass.prototype.name);
    console.log(this.name);
};

And on the page..

<script type="text/javascript">


        var myClass = new MyClass();
        myClass.init();
        myClass.SayName();

    </script>

The output is…

init
Peter set by proto
Peter set by this

So whats the differenve between proto and this I thought they both basically access the object/class…?

Answer 1

Simplly put, attribute of prototype will appear in all objects of the class, and attribute of the object just belongs to this object.

you set:

MyClass.prototype.name = 'Peter set by prototype';

and you console.log:

console.log(new MyClass().name);
console.log(new MyClass().name);
....

all of them would show ‘Peter set by prototype’.

and if you set:

var myClass = new MyClass();
myClass.name = "Peter set by object";

and you console.log:

console.log(new MyClass().name);
console.log(myClass.name);
....

would show:

Peter set by prototype
Peter set by object