rennanadeMacBook-Pro:~ rennana$ npm install -g @vue/cli
npm WARN deprecated request@2.88.2: request has been deprecated, see https://github.com/request/request/issues/3142
npm WARN deprecated urix@0.1.0: Please see https://github.com/lydell/urix#deprecated
npm WARN deprecated resolve-url@0.2.1: https://github.com/lydell/resolve-url#deprecated
npm WARN deprecated chokidar@2.1.8: Chokidar 2 will break on node v14+. Upgrade to chokidar 3 with 15x less dependencies.
npm WARN deprecated fsevents@1.2.13: fsevents 1 will break on node v14+ and could be using insecure binaries. Upgrade to fsevents 2.
npm WARN checkPermissions Missing write access to /usr/local/lib/node_modules
npm WARN jscodeshift@0.9.0 requires a peer of @babel/preset-env@^7.1.6 but none is installed. You must install peer dependencies yourself.
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.
npm ERR! A complete log of this run can be found in:
npm ERR! /Users/rennana/.npm/_logs/2020-06-10T09_05_12_847Z-debug.log
解决方法：
这种error信息一般出现在mac电脑安装某个依赖到全局的情况下，这是因为你的权限不够，无法将此模块安装到全局环境。只需要在你的npm命令前面加上一个sudo即可。
sudo npm install xxx -g