Npm install -g contextify reported an error.

  node.js, question

npm install -g contextify

npm ERR!  node v5.1.1
 npm ERR!  npm  v3.3.12
 npm ERR!  code ELIFECYCLE
 npm ERR!  contextify@0.1.15 install: `node-gyp rebuild`
 npm ERR!  Exit status 1
 npm ERR!
 npm ERR!  Failed at the contextify@0.1.15 install script 'node-gyp rebuild'.
 npm ERR!  Make sure you have the latest version of node.js and npm installed.
 npm ERR!  If you do, this is most likely a problem with the contextify package,
 npm ERR!  not with npm itself.
 npm ERR!  Tell the author that this fails on your system:
 npm ERR!  node-gyp rebuild
 npm ERR!  You can get their info via:
 npm ERR!  npm owner ls contextify
 npm ERR!  There is likely additional logging output above.

refer to
Vs2012 and python2.7 are already installed.

This plug-in has not been installed. You can try to update node and npm. Perhaps the current version of this plug-in requires the version of node and npm. Your native node and npm may not be up to the required version.