The following code:

var i = 0, j = 0;


class Base {
    get instanceAccessor() { return ++i; }
    static get staticAccessor() { return ++j; }
    toString = () => 'instance: ' + this.instanceAccessor + '   static: ' + Base.staticAccessor;
}


class Derived extends Base {
    toString = () => 'instance: ' + this.instanceAccessor + '   static: ' + Derived.staticAccessor;
}


console.log('Base:\n%s\n%s\n%s', new Base(), new Base(), new Base());
console.log('Derived:\n%s\n%s\n%s', new Derived(), new Derived(), new Derived());

generates the following output (with the v1.3 compiler):

Base:
instance: 1   static: 2
instance: 2   static: 3
instance: 3   static: 4
Derived:
instance: 4   static: 1
instance: 5   static: 1
instance: 6   static: 1

Clearly Derived.staticAccessor is no longer an accessor, but a 'snapshot' of the value of Base.staticAccessor when the Derived constructor function called __extends.

Just wondering if this is the expected/correct behaviour?

PS. I haven't run into this problem 'in the wild' as I rarely use classes or accessors, but merely came across a rant/blog post about another compile-to-JS language doing something similar, and was curious how TypeScript handled it.