```js function cmp (a, b) { return a < b ? -1 : a > b ? 1 : 0 } ``` merge seems to choke if the return value is 0 **solution** change the default to fall back to e.g. 1 (or oscillate between 1/ -1)
merge seems to choke if the return value is 0
solution change the default to fall back to e.g. 1 (or oscillate between 1/ -1)