Sharepoint Framework Configuration with Proxy server - Autentication Error - Resolution

Step 1 : Installation of Node JS.
Step 2: Installation of Yeoman and gulp. if the development environment is behind the proxy server. installation wont happens.

You have to configure proxy server with the following command.

npm config set proxy http://proxy.company.com:8080
npm config set https-proxy http://proxy.company.com:8080

normally it works.

if you got the following error. Authentication is required for Proxy.

Error
npm ERR! registry error parsing json
npm ERR! registry error parsing json
npm ERR! Unexpected token A
npm ERR! Authentication Required
npm ERR! npm ERR! npm ERR! If you need help, you may report this error at:
npm ERR!

Resolution
you have to set proxy with authentication

npm config set proxy http://username:password@proxy.example.com:8080
npm config set https-proxy http://username:password@proxy.example.com:8080