Switching between proxy and no-proxy config in .bash_profile
You may create a separate shell script and source it whenever you are at a "non-proxified" location. For example, I have a .unset_proxy.sh under my user directory that I source whenever I need to get work done at home or starbucks. This is what it looks like:

unset HTTP_PROXY
unset HTTPS_PROXY
unset http_proxy
unset https_proxy
npm config delete https-proxy
npm config delete http-proxy
npm config delete proxy


This is the command I run:
    . ~/.unset_proxy

When I'm back at the office building I simply source my bash profile to reset the proxy: 
    . ~/.bash_profile