Pardon for jumping in but fold are very well studied functions, as you know :) Sorry for dropping a link, but it speaks much better than I could: Fold Higher Order Function
@wulymammoth
your code is slightly wrong. You have to return the accumulator (the object of arrays, this case). You're instead returning whatever push returns (which is the length of the array after pushing). (Also, you're re-declaring the parameter num as a const, which isn't allowed, but that's a simpler fix.)
Pardon for jumping in but fold are very well studied functions, as you know :) Sorry for dropping a link, but it speaks much better than I could: Fold Higher Order Function
@wulymammoth your code is slightly wrong. You have to return the accumulator (the object of arrays, this case). You're instead returning whatever push returns (which is the length of the array after pushing). (Also, you're re-declaring the parameter
numas a const, which isn't allowed, but that's a simpler fix.)All good catches