离子和npm许可

我已经设置了一个离子v1项目。 现在当我input以下命令:

ionic cordova platform add ios 

我得到以下错误:

 [ERROR] Exception: Using cordova-fetch for ios Error: Failed to fetch platform ios Probably this is either a connection problem, or platform spec is incorrect. Check your connection and platform name/version/URL. Error: npm: Command failed with exit code 194 Error output: npm WARN checkPermissions Missing write access to /Users/tom/Documents/node_modules/ios npm WARN enoent ENOENT: no such file or directory, open '/Users/tom/Documents/package.json' npm WARN Documents No description npm WARN Documents No repository field. npm WARN Documents No README data npm WARN Documents No license field. npm ERR! path /Users/tom/Documents/node_modules/ios npm ERR! code ELOOP npm ERR! errno -62 npm ERR! syscall access npm ERR! ELOOP: too many symbolic links encountered, access '/Users/tom/Documents/node_modules/ios' 

我该如何解决这个错误?