我把node升级到4.2.1版本，可是本地目录还是0.12的。

usr/local/Cellar/node/0.12.2_1

好像不影响使用，但我想知道原因。 另，其实原本我直接升级到5.0的，然后就出错了。

npm ERR! Darwin 15.0.0 npm ERR! argv “/usr/local/Cellar/node/0.12.2_1/bin/node” “/usr/local/bin/npm” “install” “gulp-sass” npm ERR! node v5.0.0 npm ERR! npm v3.3.6

npm ERR! Cannot read property ‘localeCompare’ of undefined npm ERR! npm ERR! If you need help, you may report this error at: npm ERR! https://github.com/npm/npm/issues

npm ERR! Please include the following file with any support request: npm ERR! /Users/LiaoYingRay/Projects/coding/rayliao/npm-debug.log