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Asked: 2026-06-05T07:49:18+00:00

i have made two classes, which is person – the parent class and a

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i have made two classes, which is person – the parent class and a student class – the child class. i am trying to implement inheritance. also i am trying to implement it in modular pattern. but its not getting properly. for the code block please check below.

Person.js

var Person = function() {

    var details, constructor, getDetailsByAttribute, setDetailsByAttribute, setDetails, getDetails, clearDetails;

    clearDetails = function()   {
        details = {
            uid : '',
            name : '',
            email : ''
        };
    };

    getDetailsByAttribute = function(attr)  {
        return details[attr];
    };

    setDetailsByAttribute = function(key, value)    {
        if(details.hasOwnProperty(key)) {
            details[key] = value;
        }else   {
            console.log('invalid key');
        }
    };

    setDetails = function(param)    {
        clearDetails();
        for(var attr in param)  {
            if(details.hasOwnProperty(attr))    {
                details[attr] = param[attr];
            }
        }
    };

    getDetails = function() {
        return details;
    };

    /**
     * During object creation;
     */
    if(arguments.length >= 1)   {
        //clearDetails();
        setDetails(arguments[0]);
    }

    return {
        getDetailsByAttribute : function(attr)  {
            return getDetailsByAttribute(attr);
        },

        setDetailsByAttribute : function(key, value)    {
            setDetailsByAttribute(key, value);
        },

        setDetails : function(params)   {
            setDetails(params);
        },

        getDetails : function() {
            return getDetails();
        },

        clearDetails : function()   {
            clearDetails();
        }
    };
};

Student.js

var Student = function()    {
    Person.call(this,arguments);
};

Student.prototype = new Person();

index.html

<html>
    <head>
    </head>
    <body>
        <script type="text/javascript" src="modules/Person.js"></script>
        <script type="text/javascript" src="modules/Student.js"></script>
        <script type="text/javascript">
            var person1, person2, person3, student1;

            person1 = new Person({
                uid : 5225,
                name : 'jaison',
                email : 'jaison@jaison.com'
            });

            person2 = new Person({
                uid : 5222,
                name : 'jatin',
                email : 'jatin@jatin.com'
            });

            person3 = new Person();
            person3.setDetails({
                uid : 5221,
                name : 'sarath',
                email : 'sarath@sarath.com'
            });
            person3.setDetailsByAttribute('name', 'sarath');

            student1 = new Student({
                uid : 5221,
                name : 'sachin',
                email : 'sachin@sachin.com'
            });

            console.log('person 1 : ',person1.getDetails());
            console.log('person 2 : ',person2.getDetails());
            console.log('person 3 : ',person3.getDetails());
            console.log('student 1 : ',student1.getDetails());
            //console.log(student1.get);

        </script>
    </body>
</html>
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1 Answer

  1. Editorial Team

    try this:

    var Student = function()    {
    return Person.apply(this, arguments);
};

    without 

    Student.prototype = new Person();

    UPDATE: I just realize that you can use this:

    var Student = function()    {
    this.setDetails.apply(this, arguments);
};
Student.prototype = new Person();

    So the closure will be inside prototype, and setDetails will access it.

    In your code when you do this:

    Student.prototype = new Person();

    you create a closure and when You call this

    var Student = function()    {
    Person.call(this,arguments);
};

    you create another closure (and it should not be call but apply, but even that it will not work). you execute constructor as a function and (if it will be apply it will) apply arguments to different closure, and all those functions that are returned by Person with detail inside the closure will be discard. methods of Student will be taken from prototype not from constructor.

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