[cmbaus]

In JavaScript, like other duck typed languages, you have dynamic dispatch without inheritance.

For example:

    var objA = {doIt:function(){console.log('hello from a')}};
    var objB = {doIt:function(){console.log('hello from b')}};
    
    var doItDynamically = function(doitObj) {
        doitObj.doIt();
    };
   
    doItDynamically(objA);
    doItDynamically(objB);

a and b do not share a common class (since classes do not exist in JavaScript), but they implement the same interface. For this reason, they can be used polymorphically, as if they shared a common base class or interface in Java or C++.