clean if statements in shell

if.sh

# dens form for short statements / commands
if [[ -n "${bla:-}" ]]
then x=bla
else x=
fi

# sparse form for long statements / more commands
if
  [[ -n "${bla_asd_sf_affdfs_dsf_sdf_sdf:-}" ]] ||
  [[ -n "${bar_Dfs_dsg_FG_fd_fd_df_dfgdf:-}" ]]  
then
  some more commands
  and even more
else
  or other commands
fi

# mixed for large else
if [[ -n "${bla:-}" ]]
then x=bla
else
  x=...
  some more commands
  and even more
fi

# just else
[[ -n "${bla:-}" ]] ||
{
  x=...
  some more commands
  and even more
}