Nor in 0.8.23. I think the chaining of the constructor to .fill in `var sieve = new SB(len).fill(0xff, 0, len);` is the issue, because SlowBuffer::fill isn't supposed to have a return value.

Ah yeah. I forgot that Buffer#fill() only returns "this" in master. I updated the example to fix this.

think it might be because fill may not return a value, prob just need to call sieve.fill on a separate line after you declare it.