Convention for prototype inheritance in JavaScript

Question

I see a lot of code like this:

function Base() {}
function Sub() {}
Sub.prototype = new Base();

However, if you do:

s = new         


        

Answer 1

If you want to test whether an object is exactly an instance of Sub use the instanceof operator:-

print(s instanceof Sub);

If you want to know whether an object is an instance of Sub or an instance of a sub-class of Sub use the isPrototypeOf method:-

print(Sub.prototype.isPrototypeOf(s));