In the following piece of code, how can I access the A.prototype.log inside of B.prototype.log?

function A() {}

A.prototype.log = function () {
    console.log("A");
};

function B() {}

B.prototype = Object.create(A.prototype);
B.prototype.constructor = B;

B.prototype.log = function () {
    //call A.prototype.log here
    console.log("B");
};

var b = new B();
b.log();

I know I could just write A.prototype.log.call(this) but I thought maybe there is a more elegant way, that lets me call it in a relative way, like "call the method 'log' of the next higher instance in the prototype chain". Is something like this possible?

In the following piece of code, how can I access the A.prototype.log inside of B.prototype.log?

function A() {}

A.prototype.log = function () {
    console.log("A");
};

function B() {}

B.prototype = Object.create(A.prototype);
B.prototype.constructor = B;

B.prototype.log = function () {
    //call A.prototype.log here
    console.log("B");
};

var b = new B();
b.log();

I know I could just write A.prototype.log.call(this) but I thought maybe there is a more elegant way, that lets me call it in a relative way, like "call the method 'log' of the next higher instance in the prototype chain". Is something like this possible?

• javascript
• inheritance
• overriding
• prototype

• 1 actually, A.prototype.log.call(this) was exactly what I searched for. Thank you! – ProblemsOfSumit Commented Nov 18, 2014 at 9:30

1 Answer 1

You could use Object.getPrototypeOf

...
B.prototype.log = function () {
    Object.getPrototypeOf (B.prototype).log.call(this)
    console.log("B");
};
...
b.log(); //A B

Note: Object.getPrototypeOf is ECMASript 5, see the patibility

There is also the non standard and deprecated __proto__ property (patibility) which

references the same object as its internal [[Prototype]]

and would allow you to call your As' log method like this

B.prototype.__proto__.log.call(this)

But

the preferred method is to use Object.getPrototypeOf.