macbook 安装 BrowserSync,终端输入npm install -g browser-sync报错？？

Last login: Fri Apr  5 13:01:36 on ttys000

192:~ apple1$ npm install -g browser-sync

npm WARN checkPermissions Missing write access to /usr/local/lib/node_modules

npm ERR! path /usr/local/lib/node_modules

npm ERR! code EACCES

npm ERR! errno -13

npm ERR! syscall access

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!   stack:

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! 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 (though this is not recommended).

npm ERR! A complete log of this run can be found in:

npm ERR!     /Users/apple1/.npm/_logs/2019-04-05T05_04_43_441Z-debug.log

192:~ apple1$