missing property in IteratorResult<T> object on page 50 example

Hi,

Thanks for the great work on this book, I'm loving reading it.

I just noticed that on es6 iterator example in page 50 (pdf version) there is a missing value property on next() method.

ES6 interface definition for IteratorResult requires the value to be defined :
interface IteratorResult {
done: boolean;
value: T;
}

so on the next() else case the return should be something like:
return {
value: null,
done: true
}

Hope this helps.

Regards

Locate the ES6 iterator example on page 50 of the PDF and compare its next() result with the IteratorResult interface shown in the issue. Update the example so the final result includes the missing value property, then verify the corrected example in the book source and rendered PDF.

Written by the indexing model from the issue text.