gistfile1.js

function Base() {
}
Base.foo = 'foo';

function Derived() {
    Base.call(this);
}
Derived.prototype = Object.create(Base.prototype);
// Derived.prototype.constructor = Derived; // {1}
Derived.bar = 'bar';

var d = new Derived();
console.log('(1) keys(d)', Object.keys(d));
console.log('(2) keys(d.constructor) =', Object.keys(d.constructor)); // why no 'bar' ??!!!

// if uncomment {1} then I get 'bar' but do not get 'foo'