sara@saraslaptop:~/Desktop$ npx create-react-app
Error: EPERM, Operation not permitted
    at /home/sara/.nvm/versions/node/v11.4.0/lib/node_modules/npm/node_modules/uid-number/uid-number.js:49:16
    at ChildProcess.exithandler (child_process.js:285:7)
    at ChildProcess.emit (events.js:189:13)
    at maybeClose (internal/child_process.js:978:16)
    at Process.ChildProcess._handle.onexit (internal/child_process.js:265:5)
TypeError: Cannot read property 'get' of undefined
    at errorHandler (/home/sara/.nvm/versions/node/v11.4.0/lib/node_modules/npm/lib/utils/error-handler.js:205:18)
    at /home/sara/.nvm/versions/node/v11.4.0/lib/node_modules/npm/bin/npm-cli.js:78:20
    at cb (/home/sara/.nvm/versions/node/v11.4.0/lib/node_modules/npm/lib/npm.js:228:22)
    at /home/sara/.nvm/versions/node/v11.4.0/lib/node_modules/npm/lib/npm.js:266:24
    at /home/sara/.nvm/versions/node/v11.4.0/lib/node_modules/npm/lib/config/core.js:83:7
    at Array.forEach (<anonymous>)
    at /home/sara/.nvm/versions/node/v11.4.0/lib/node_modules/npm/lib/config/core.js:82:13
    at f (/home/sara/.nvm/versions/node/v11.4.0/lib/node_modules/npm/node_modules/once/once.js:25:25)
    at afterExtras (/home/sara/.nvm/versions/node/v11.4.0/lib/node_modules/npm/lib/config/core.js:173:20)
    at Conf.<anonymous> (/home/sara/.nvm/versions/node/v11.4.0/lib/node_modules/npm/lib/config/core.js:231:22)
/home/sara/.nvm/versions/node/v11.4.0/lib/node_modules/npm/lib/utils/error-handler.js:205
  if (npm.config.get('json')) {
                 ^

TypeError: Cannot read property 'get' of undefined
    at process.errorHandler (/home/sara/.nvm/versions/node/v11.4.0/lib/node_modules/npm/lib/utils/error-handler.js:205:18)
    at process.emit (events.js:189:13)
    at process._fatalException (internal/bootstrap/node.js:627:27)
Install for create-react-app@latest failed with code 7