I am a fan of keeping .bashrc as close to system default setting as possible and instead manage the shell customization

$HOME/.bash.d

I put the following script at the end of my .bashrc file to add all the $HOME/.bash.d/*.sh scripts to the .bashrc launch. It also allows for .sh.mac scripts for customizing my mac workstations (don't use those anymore but keep the code around just in case I do). It also allows for a system specific script to be added for host specific customizations of bashrc by looks for a match to a $HOSTNAME.sh.host script

if [ -d $HOME/.bash.d ]; then
  for I in $HOME/.bash.d/*.sh; do
    source $I
  done
  if [[ ${OSTYPE//[0-9.]/} == 'darwin' ]]; then
    for I in  $HOME/.bash.d/*.sh.mac; do
      source $I
    done
  fi
  if [ -f $HOME/.bash.d/$HOSTNAME.sh.host ]; then
    . $HOME/.bash.d/$HOSTNAME.sh.host
  fi
fi