这种情况你需要重新安装npm， 推荐使用homebrew安装， 或者直接从源码安装： 

源码安装方法：

git clone http://github.com/isaacs/npm.git

cd npm
sudo make install

或者使用npm官网的安装脚本

curl http://npmjs.org/install.sh | sudo sh

然后再按照我们课程介绍的重试就可以了

老师  我是window 7 操作系统，配置 sudo 好久了~~有啥好方法没

还有这个错误｀｀

xcode-select: error: tool 'xcodebuild' requires Xcode, but active developer directory '/Library/Developer/CommandLineTools' is a command line tools instance

用sudo运行也是这样

npm ERR! Error: EACCES, mkdir '/Users/superman/.npm/source-map/0.1.41'

npm ERR!  { [Error: EACCES, mkdir '/Users/superman/.npm/source-map/0.1.41']

npm ERR!   errno: 3,

npm ERR!   code: 'EACCES',

npm ERR!   path: '/Users/superman/.npm/source-map/0.1.41',

npm ERR!   parent: 'karma' }

npm ERR! 

npm ERR! Please try running this command again as root/Administrator.

npm ERR! System Darwin 14.0.0

npm ERR! command "node" "/usr/local/bin/npm" "install" "karma-phantomjs-launcher" "karma-jasmine" "grunt-karma" "--save-dev"