If you have execution timeout, then the solution does not pass, despite of returning correct answers.

See if this paragraph helps.

Object.keys doesn't work on an iterable object ( well, it does, but it doesn't do what you want it to do ). You have to iterate it. Follow the link in the description and read up on the protocol.

This question was already answered here.

               v                           v   v
expected [ 9, +0, 9, 1, 2, 1, 1, 3, 1, 9, +0, +0, 9, +0, +0, +0, +0, +0, +0, +0 ] to deeply equal 
         [ 9, 9, 1, 2, 1, 1, 3, 1, 9, 9, +0, +0, +0, +0, +0, +0, +0, +0, +0, +0 ]

The first value there is your answer, and you can see there are more than one 0 not at the end. Probably you're mutating the array at the same time you run through it, skipping values.

About what +0 is, you can see that's 0, don't mind the + before it, it's probably chai adding it in the assertion.

no, it returns with commas

There is a trick to do it, which doesnt require searching for every possible combination. Hint: think about why its specifically powers of 2?