Running npm install directly from a repository in a Enterprise account will fail:

$ ~: npm i
npm ERR! Error while executing:
npm ERR! /usr/local/bin/git ls-remote -h -t https://github.com/<Enterprise>/<repo>.git
npm ERR!
npm ERR! remote: Invalid username or password.
npm ERR! fatal: Authentication failed for 'https://github.com/<Enterprise>/<repo>.git'
npm ERR!
npm ERR! exited with error code: 128

git uses curl under the hood. You can create a configuration file at ~/.netrc, which could look something like this:

machine github.com
  login goliatone
  password ccbceb69bfd1421dbc7d4cc6d6f87d9a...

The access token you generate in github at Settings > Developer settings > Personal access tokens.

If you are using SSO, make sure to enable the option after the token is created.

The first time you try to pull it could potentially fail again, but the error message might send you to github in order to approve the credential:

$ ~: npm i
npm ERR! Error while executing:
npm ERR! /usr/local/bin/git ls-remote -h -t https://github.com/<Enterprise>/<repo>.git
npm ERR!
npm ERR! remote: The `WeConnect' organization has enabled or enforced SAML SSO. To access
npm ERR! remote: this repository, visit https://github.com/orgs/<Enterprise>/sso?authorization_request=b35fecca648848dcbd960f0e288c3eaa-hs3b_W505702eb5d11314957a9f04ac9f8a46d93z
npm ERR! remote: and try your request again.
npm ERR! fatal: unable to access 'https://github.com/<Enterprise>/<repo>.git/': The requested URL returned error: 403
npm ERR!
npm ERR! exited with error code: 128