tail call length still hits call stack

[adamdawkins]

Hi,

I was reading http://raganwald.com/2015/02/07/tail-calls-defult-arguments-recycling.html, and it's fascinating stuff, thank you.

However, I was doing some testing myself, and I found that the tail call version of length() still hits Maximum call stack size exceeded at ~ 8,400 item long arrays on my Macbook Pro

Is this because of the inefficiency of [first, ...rest]. My understanding of the article was that the recursion was now ok because JavaScript optimizes away the function call overhead and stack space.

I'm just finding both the tail call length and the inefficient one fall over at the same point:

const length = ([first, ...rest], numberToBeAdded = 0) =>
  first === undefined
    ? numberToBeAdded
    : length(rest, 1 + numberToBeAdded)

[raganwald]

Where are you running this? Although the JS spec says that tail recursion is optimized, Google refused to implement that on V8, therefore it does not get optimized on node or chrome.safari implements it, that's where I test most of the code.

If this still fails on safari, I'll figure out the issue. It could also be the difference between a ternary ?: and an if statement, depending on how the tail detection is implemented.