Can you assign the prototype of a Constructor to another Constructor?

Question

Lets say you have a constructor ConstrA and want it to inherit from another constructor named SuperConstr and its prototype.

Can you simply do this:

SuperConstr = function() {};
SuperConstr.prototype.show = function (parm) {
    window.console.log(parm);
}
ConstrA = function () {
    this.value = 1;
}
ConstrA.prototype = SuperConstr.prototype; // <-----  Is this valid?
ConstrA.prototype.showAgain = function (parm) {
    window.console.log(parm * 2);
}
obj = new ConstrA();
obj.show(obj.value); // 1
obj.showAgain(obj.value); // 2

obj now appears to inherit from ConstrA and SuperConstr, but I'm not sure this is the right way to do this.

In other words, is the prototype of a constructor suppose to be equal (point to) the prototype of its constructor?

Answer 1

It's valid, but you no longer have two prototype objects, just the one.

So any methods you're trying to delegate won't actually be delegated, they will all exist on SuperConstr's prototype object.

A concern with this is that if you extend ConstrA's prototype, you're actually assigning to SuperContr's prototype, which is probably not what you want.