What does "set -- command doas $@" do in my Bash function?

I use this Bash oneliner, set -o errexit;set -o pipefail;set -o nounset;doas() { [[ "${EUID}" == '0' ]]||set -- command doas "${@}";"${@}";} in the head of my scripts in order to prevent me from being asked for a password when I'm root. From what I gathered , if any arguments follow --, then the the positional parameters are set to the arguments. What does commanddo in my oneliner? Is it a Bash bult-in (which command returns nothing)? Would someone decode it and give another example of using command. Where can I read more about command?