NPM not working under any circumstances

Hello,

I am trying to run NPM on my Mac but it is having the same issue. I have followed all the steps to try and fix this, but when I install after un-insttalling, I get npm WARN checkPermissions Missing write access to /usr/local/lib/node_modules
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.

And I cannot run the npm to local host. When I try using npm run, I get this;

npm run
Lifecycle scripts included in react-redux-router:
preinstall
npm set audit false
start
webpack-dev-server --config webpack/dev.config.js --watch

available via npm run-script:
build
cross-env NODE_ENV=production webpack --config webpack/prod.config.js --progress --display-error-details --color
heroku-postbuild
npm run build
precommit
eslint src
prod
NODE_ENV=production node server.js

I tried to run delete node_modules but it said I did not recognize the command. Both NPM and Node are updated to their lastest updated versions, npm at 6.14.5 and node at v14.5.0. My mac is running Catalina 10.15.5. Any idea why this is happening or how I can fix it?
Describe the bug

To Reproduce

I just go into my npm and try to start it or run it and I get the output above.
Expected behavior
for it to run my project on localhost:3000 so I can see my work
Sample project

Additional context
Please let me know if you have any questions.

報告提到 npm 6.14.5、Node v14.5.0、macOS Catalina，以及一個使用 webpack/dev.config.js 的 React 專案。首先重現 /usr/local/lib/node_modules 的 EACCES 錯誤和 npm run 失敗，然後確定問題屬於 NativeScript CLI 還是本機 npm 權限。確認了專案特定的重現，並驗證了 localhost 啟動路徑後，才算完成。