object unshift

object unshift

i don't know if i need a js forums but..how do i unshift a object please?

  1. Object { 1: File, 3: File, 4: File, 5: File }

in this scenario how i make key 5 appear at the beginning of the object? like so:

  1. Object { 5: File, 1: File, 3: File, 4: File}

thank you