npm showing severity vulnerabilities Laravel

npm showing severity vulnerabilities, but using

npm chache clear
npm cache clear --force
npm audit fix
npm install

I have tried all of them but none of these solving my problem, please give some idea how I can solve it?

npm WARN optional SKIPPING OPTIONAL DEPENDENCY: fsevents@1.2.4 (node_modules\fsevents):
npm WARN notsup SKIPPING OPTIONAL DEPENDENCY: Unsupported platform for fsevents@1.2.4: wanted {"os":"darwin","arch":"any"} (current: {"os":"win32","arch":"x64"})

added 1505 packages from 755 contributors and audited 18951 packages in 378.007s
found 11 moderate severity vulnerabilities
  run `npm audit fix` to fix them, or `npm audit` for details

via Chebli Mohamed