Refactor: V2. Change StateDB to class based architecture.

[saurabhg772244]

📑 Summary

• Refactors the existing stateDb implementation from a functional approach to a class-based architecture to improve code organization, maintainability, and extensibility.
• Return a new DB object when diagramObject.db is called.
• Introduces new StateDB class to encapsulate database operations and state
• Migrates existing functions to class methods
• Maintains existing API interface for backwards compatibility
• Following functions still uses common DB:
  • getConfig
  • getAccTitle
  • setAccTitle
  • getAccDescription
  • setAccDescription
  • getDiagramTitle
  • setDiagramTitle
• Reason why above functions still uses common DB: Refactor: Change flowDB to class based architecture. #6161 (comment)
• Fixed issue where the DB remained empty after parsing and was only set during rendering. Previously, after parsing values were only being set in rootDoc, but the DB was not updated. Now, the DB is set using the extract function when setRootDoc is called.
• Removed extract method from all unit tests since the parser now directly sets the data in the db, making extract unnecessary.

Previous PR: #6185

Revert PR: #6218

📏 Design Decisions

• The stateDb module previously relied on functions and global variables. Consequently, each call to mermaid.parse or mermaid.render resulted in changes to global variables.
• This behavior caused issues when rendering multiple diagrams using the same Mermaid API, as the database object (DB) for the diagrams would get mixed up.
• To address this, stateDb was refactored into a class-based structure. This change ensures that each diagramObject.db call creates a new instance of the database (DB), preventing conflicts between diagrams.

📋 Tasks

Make sure you

• 📖 have read the contribution guidelines
• 💻 have added necessary unit/e2e tests.
• 📓 have added documentation. Make sure MERMAID_RELEASE_VERSION is used for all new features.
• 🦋 If your PR makes a change that should be noted in one or more packages' changelogs, generate a changeset by running pnpm changeset and following the prompts. Changesets that add features should be minor and those that fix bugs should be patch. Please prefix changeset messages with feat:, fix:, or chore:.

[changeset-bot]

🦋 Changeset detected

Latest commit: 4dbaa2b

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
mermaid	Patch

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[netlify]

✅ Deploy Preview for mermaid-js ready!

Name	Link
🔨 Latest commit	4dbaa2b
🔍 Latest deploy log	https://app.netlify.com/sites/mermaid-js/deploys/67a21b3da4802d00082d14b4
😎 Deploy Preview	https://deploy-preview-6250--mermaid-js.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.

---

To edit notification comments on pull requests, go to your Netlify site configuration.

[pkg-pr-new]

Open in Stackblitz

npm i https://pkg.pr.new/mermaid-js/mermaid@6250

npm i https://pkg.pr.new/mermaid-js/mermaid/@mermaid-js/mermaid-zenuml@6250

npm i https://pkg.pr.new/mermaid-js/mermaid/@mermaid-js/layout-elk@6250

npm i https://pkg.pr.new/mermaid-js/mermaid/@mermaid-js/parser@6250

commit: 4dbaa2b

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 581 lines in your changes missing coverage. Please review.

Project coverage is 4.47%. Comparing base (8dd0e7a) to head (4dbaa2b).

Files with missing lines	Patch %	Lines
packages/mermaid/src/diagrams/state/stateDb.js	0.00%	567 Missing ⚠️
packages/mermaid/src/diagrams/state/shapes.js	0.00%	6 Missing ⚠️
...ages/mermaid/src/diagrams/state/stateDiagram-v2.ts	0.00%	4 Missing ⚠️
...ackages/mermaid/src/diagrams/state/stateDiagram.ts	0.00%	4 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           develop   #6250      +/-   ##
==========================================
- Coverage     4.47%   4.47%   -0.01%     
==========================================
  Files          385     385              
  Lines        54191   54244      +53     
  Branches       598     598              
==========================================
  Hits          2425    2425              
- Misses       51766   51819      +53     

Flag	Coverage Δ
unit	4.47% <0.00%> (-0.01%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
...aid/src/diagrams/state/stateRenderer-v3-unified.ts	0.00% <ø> (ø)
...ages/mermaid/src/diagrams/state/stateDiagram-v2.ts	0.00% <0.00%> (ø)
...ackages/mermaid/src/diagrams/state/stateDiagram.ts	0.00% <0.00%> (ø)
packages/mermaid/src/diagrams/state/shapes.js	0.00% <0.00%> (ø)
packages/mermaid/src/diagrams/state/stateDb.js	0.00% <0.00%> (ø)