What it the significance of the Javascript constructor property?

Question

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 signif

Answer 1

One of the use cases when you would want the prototype.constructor property to survive prototype property reassignment is when you define a method on the prototype that produces new instances of the same type as the given instance. Example:

function Car() { }
Car.prototype.orderOneLikeThis = function() {  // Clone producing function
    return new this.constructor();
}
Car.prototype.advertise = function () {
    console.log("I am a generic car.");
}

function BMW() { }
BMW.prototype = Object.create(Car.prototype);
BMW.prototype.constructor = BMW;              // Resetting the constructor property
BMW.prototype.advertise = function () {
    console.log("I am BMW with lots of uber features.");
}

var x5 = new BMW();

var myNewToy = x5.orderOneLikeThis();

myNewToy.advertise(); // => "I am BMW ..." if `BMW.prototype.constructor = BMW;` is not 
                      // commented; "I am a generic car." otherwise.