generator throwing excaptions

generator_simple.harmony.js

var throwing = function *(){
    console.log('Generator entered, yielding first value');
    yield 1;
    console.log('Generator asked for second value - will go bum');
    throw new Error("You can only call this generator once, sorry!");
    console.log('Will never get here');
    yield 3;
};

var throwingGenerator = throwing();

throwingGenerator.next();
try {
  throwingGenerator.next();
} catch (e) {
  console.error(e);
}