git branch into the `prompt` variable in ZSH (Mac Terminal)

.zshrc

# inspired by:
#   https://medium.com/pareture/simplest-zsh-prompt-configs-for-git-branch-name-3d01602a6f33
#   https://medium.com/dev-genius/customize-the-macos-terminal-zsh-4cb387e4f447
#   http://zsh.sourceforge.net/Doc/Release/Prompt-Expansion.html#Prompt-Expansion


# Find and set branch name var if in git repository.
function git_branch_name()
{
  branch=$(git symbolic-ref HEAD 2> /dev/null | awk 'BEGIN{FS="/"} {print $NF}')
  if [[ $branch == "" ]];
  then
    :
  else
    echo ' - ('$branch')'
  fi
}

# Enable substitution in the prompt.
setopt prompt_subst

# Config for prompt. PS1 synonym.
# miguel@~/repo - (master) > 
prompt='%F{red}%n%f@%F{green}%~%f%F{magenta}$(git_branch_name)%f > '