Node NPM proxy authentication - how do I configure it?

I'm new to Node and trying to install TypeScript using the following command: ``` npm install -g typescript ``` I get the following error: ``` if you are behind a proxy, please make sure that the 'proxy' config is set properly. ``` I have set my proxy using the following commands: ``` npm config set proxy http://Username:Pa55w0rd@proxyhostname npm config set https-proxy http://Username:Pa55w0rd@proxyhostname ``` and tried this also: ``` npm config set proxy http://"ninjadev:5trongP@ssw0rd"@proxy.some-bigcorp.com npm config set https-proxy http://"ninjadev:5trongP@ssw0rd"@proxy.some-bigcorp.com ``` But none of them work. I am working behind a copmpany proxy with authentication, so I think this is stopping me from connecting. I have added my username and password and this also didn't work. Does anyone have any idea how I can connect to npm whilst using the company proxy and authentication? Thanks