This ES2018+ Javascript RegExp expression should parse the components of any valid Docker image reference URI.

It captures:

• Name
  • ?Host
    • ?Domain
    • ?Port
  • ?Namespace
  • Repo
• ?Reference
  • ?Tag
  • ?Digest

This expression uses named capture groups and lookarounds, which are available from ES2018. Be sure to check compatibility! See here for a good reference: https://www.smashingmagazine.com/2019/02/regexp-features-regular-expressions/#compatibility-table

The expression itself is based on a literal transcription of the RegEx from the official Go implementation / spec: https://pkg.go.dev/github.com/docker/distribution/reference

There is one notable deviation here from the spec -- I have separated the 'Path' component into two parts -- 'Namespace' and 'Repo'. This is helpful for registries which have container paths more than two levels deep (e.g. GitLab's.) So, in the case of registry.xyz/myorg/mygroup/myproject:latest, it would extract myorg/mygroup as "namespace" and myproject as "repo".

Hope this is helpful for someone!