解决mac系统中npm全局安装提示没有权限的问题

当使用npm或者cnpm安装全局模块时，提示报错信息：

LDX@admin88 ~ % npm install --global nodemon
npm WARN checkPermissions Missing write access to /usr/local/lib/node_modules
npm ERR! code EACCES
npm ERR! syscall access
npm ERR! path /usr/local/lib/node_modules
npm ERR! errno -13
npm ERR! Error: EACCES: permission denied, access '/usr/local/lib/node_modules'
npm ERR!  [Error: EACCES: permission denied, access '/usr/local/lib/node_modules'] {
npm ERR!   errno: -13,
npm ERR!   code: 'EACCES',
npm ERR!   syscall: 'access',
npm ERR!   path: '/usr/local/lib/node_modules'
npm ERR! }
npm ERR! 
npm ERR! The operation was rejected by your operating system.
npm ERR! It is likely you do not have the permissions to access this file as the current user
npm ERR! 
npm ERR! If you believe this might be a permissions issue, please double-check the
npm ERR! permissions of the file and its containing directories, or try running
npm ERR! the command again as root/Administrator.

　　解决方法：  修改用户权限

sudo chown -R $(whoami) $(npm config get prefix)/{lib/node_modules,bin,share}

　　重新使用npm安装全局模块就可以了

LDX@admin88 express % nodemon app.js              
[nodemon] 2.0.1
[nodemon] to restart at any time, enter `rs`
[nodemon] watching path(s): *.*
[nodemon] watching extensions: js,mjs,json
[nodemon] starting `node app.js`
app is running at port 3001