Calling a super function from a subclass function

Question

I am looking to call a superclass function within a subclass function that overrode the superclass function. For Example:

var a = function(x) {
    this.val = x || 0;
};
a.prototype.print = function() {
    console.log("Class A");
};

var b = function(x, y) {
   this.y = y || 0;
   a.call(this, x);
};
b.prototype = Object.create(a.prototype);
b.prototype.constructor = b;
b.prototype.print = function() {
    console.log("b inherits from ");
    // call to superclass print function (a.print) 
};

How would I call the superclass print function from the subclass when the subclass already overwrote the superclass function?

score 3 · Accepted Answer · answered Dec 14 '15 at 23:21

3

You can use superclass.prototype.method.call(argThis, parameters). In your case without parameters will be a.prototype.print.call(this);

So, your code would be

var a = function(x) {
    this.val = x || 0;
};
a.prototype.print = function() {
    console.log("Class A");
};

var b = function(x, y) {
   this.y = y || 0;
   a.call(this, x);
};
b.prototype = Object.create(a.prototype);
b.prototype.constructor = b;
b.prototype.print = function() {
    console.log("b inherits from ");
    a.prototype.print.call(this);

};

answered Dec 14 '15 at 23:21

caballerog

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Will check to see if this works. – Jacob Bryan Dec 14 '15 at 23:26
You can copy/paste in your browser's console to quick check. – caballerog Dec 14 '15 at 23:27

Calling a super function from a subclass function

1 Answers1