refactor orphan map

[zhongqiuwood]

• refactor orphan map

• Targeted PR against correct branch (see CONTRIBUTING.md)

• Linked to github-issue with discussion and accepted design OR link to spec that describes this work.

• Wrote tests

• Updated relevant documentation (docs/)

• Added a relevant changelog entry to the Unreleased section in CHANGELOG.md

• Reviewed Files changed in the github PR explorer

---

For Admin Use:

• Added appropriate labels to PR (ex. wip, ready-for-review, docs)
• Reviewers Assigned
• Squashed all commits, uses message "Merge PR #XYZ: [title]" (coding standards)

[codecov-commenter]

Codecov Report

Merging #1969 (75083df) into dev (5076a1f) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##              dev    #1969   +/-   ##
=======================================
  Coverage   50.84%   50.84%           
=======================================
  Files         276      276           
  Lines       19923    19923           
=======================================
  Hits        10130    10130           
  Misses       9074     9074           
  Partials      719      719           

📣 Codecov can now indicate which changes are the most critical in Pull Requests. Learn more