Trying to bend by head around Javascript's take on OO...and, like many others, running into confusion about the constructor property. In particular, the significance of the constructor property, as I can't seem to make it have any effect. E.g.:

function Foo(age) {
    this.age = age;
}

function Bar() {
    Foo.call(this, 42);
    this.name = "baz"; 
}

Bar.prototype = Object.create(Foo.prototype); 
var b = new Bar;    

alert(b.constructor); // "Foo". That's OK because we inherit `Foo`'s prototype.
alert(b.name);        // "baz". Shows that Bar() was called as constructor.
alert(b.age);         // "42", inherited from `Foo`.

In the above example, the object b seems to have had the right constructor called (Bar) – and it inherits the age property from Foo. So why do many people suggest this as a necessary step:

Bar.prototype.constructor = Bar;

Clearly, the right Bar constructor was called when constructing b, so what impact does this prototype property have? I am curious to know what practical difference it actually makes to have the constructor property set 'correctly'—as I can't see it having any affect on which constructor is actually called after an object is created.