check this out:

const xs = {};
xs[{}] = '???';
({a : 'b'}) in xs; // true

JavaScript's object-to-string conversion is messy ;-)

of course, it for alignment only.

NOTE: The test cases for this kata are broken, but for some reason CodeWars has locked them and I cannot edit them. Specifically, the returned function is not propertly testing that old values are remembered. If and when I can fix the problem, I will, but I don't see any way to do that due to the lock.

Is this still relevant ?

it means you returned an object instead of a function. if a constructor returns a non-primitive, this is what new evaluates to; and functions are not primitives

Thanks for the approval; I changed the assignments to use single-assignment form from the kata editor. Also disabled Function, which I had forgotten

i disabled it as well, but i'm sure there are still many more ways to cheat. i mostly wanted to disable the most obvious ones and to upgrade the tests suite

invalidated

done

invalidated

It was approved by someone, however it seems you forgot one more thing to disable:

https://www.codewars.com/kata/reviews/558cd9c3a98f5f0da3000057/groups/652f2c058fb49d00018471c9

eval = require = function doNotUseEvalOrRequire() {

IMHO let's not use double assignment even in the author-facing side as it's so rare an idiom / so anti-standard-style. Two separate assignments is much clearer.

LGTM otherwise

JS fork

• properly disallowing new
• tentatively disabling eval() and require()
• upgrading assertions to use chai

For what it's worth, I was vaguely familiar with what combinators were before I started this kata so I ended up having to manually derive most of the combinators from scratch (although the derived answers I got were extremely ugly and took me 2 weeks total), yet I loved the experience cause it really helped me understand combinators properly.