CODEWITHSUNDEEP
javascriptoopinheritance
FranXh
FranXh

Reputation: 4771

Inheritance in JavaScript: Calling parent's method

The way I implement inheritance in JavaScript is shown in the example below. I am trying to call from the child class a method of the parent class. I have seen many examples online, that add the parent method to the prototype, and the use the call or apply function (but my implementation is not doing that). Is there a way to make this type of call?

function classM() //parent class
{
    this.myName = function()
    {
        console.log('parent');
    }
}

function classEM ()
{
    classM.call(this);

    this.myName = function()
    {
        console.log('child');
        //HOW DO I CALL myName() of the parent class?
    }

}


classEM.prototype = Object.create(classM.prototype);
classEM.prototype.constructor = classEM;




var rm = new classEM();
rm.myName(); //should print child and then parent

Upvotes: 0

Views: 120

Answers (1)

thefourtheye
thefourtheye

Reputation: 239683

When you do this.myName = ... in classEM, you are replacing the old myName function created by the parent with the one in classEM. So only one function exists now. Instead, you can add the myName function in the classM's prototype and inherit from it.

So the program becomes like this

function classM() {}

// Add myName to the parent
classM.prototype.myName = function() {
    console.log('parent');
}

function classEM() {
    this.myName = function() {
        // Get the parent prototype object and invoke the myName in it.
        Object.getPrototypeOf(this).myName();
        console.log('child');
    }
}

classEM.prototype = Object.create(classM.prototype);
classEM.prototype.constructor = classEM;

var rm = new classEM();
rm.myName();

Output

parent
child

Upvotes: 2

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