alias bashrc='nano ~/.bashrc && source ~/.bashrc'
I'm that lazy, but I'm quite happy with this. It simply edits my bashrc and automatically reloads the config into the current terminal. I think I just found it faffy to edit the right file on mac, only to try the thing I changed and realised I forgot to source the file too.
It also works for zshrc too, although it does take a bit longer to re-source a zshrc (maybe because I'm using oh-my-zsh).
alias zshrc='nano ~/.zshrc && source ~/.zshrc'
Just be careful editing this alias iteself. I got into a bad loop when trying this where it would constantly keep opening nano every time I closed it.