How should I set _auth in .npmrc when using a Nexus https npm registry proxy?

Sources: https://help.sonatype.com/repomanager3/nexus-repository-administration/formats/npm-registry/npm-security
& https://help.sonatype.com/repomanager3/nexus-repository-administration/formats/npm-registry/publishing-npm-packages

1. Configure registry (its important doing this before configuring the authentication in step 2, because the authentication settings will be based on the registry):

   npm config set registry=”http://localhost:8081/repository/npm-internal/”

2. Configure authentication using a line like the following example:

   npm config set _auth=”$(echo -n ‘username:password’ | base64)”

3. Check the current configuration using the following:

   npm config ls

4. Publish your npm package:

   npm publish –registry http://localhost:8081/repository/npm-internal/