and an array with floating-point numbers

No, that's a horrendous idea. Everyone in every competitive coding site will have a problem with you if you do this.

I think, at this moment only integers is correct input. I`ll add a test case for negative numbers

You get this error when not properly implementing this requirement:

handler functions can subscribe and unsubscribe handlers, but the changes should only apply to the next emit call - the handlers for an ongoing emit call should not be affected