Refactor: 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)

📏 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.
• Arrow Functions are used instead of class Fields as it is required by flow.jison

📋 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:.

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🦋 Changeset detected

Latest commit: ef9bb53

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

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commit: ef9bb53

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 576 lines in your changes missing coverage. Please review.

Project coverage is 4.48%. Comparing base (bc2cc61) to head (ef9bb53).

Files with missing lines	Patch %	Lines
packages/mermaid/src/diagrams/state/stateDb.js	0.00%	566 Missing ⚠️
...ages/mermaid/src/diagrams/state/stateDiagram-v2.ts	0.00%	4 Missing ⚠️
...ackages/mermaid/src/diagrams/state/stateDiagram.ts	0.00%	4 Missing ⚠️
packages/mermaid/src/diagrams/state/shapes.js	0.00%	2 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##           develop   #6185   +/-   ##
=======================================
  Coverage     4.47%   4.48%           
=======================================
  Files          383     382    -1     
  Lines        54142   54129   -13     
  Branches       596     621   +25     
=======================================
  Hits          2425    2425           
+ Misses       51717   51704   -13     

Flag	Coverage Δ
unit	4.48% <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
packages/mermaid/src/diagrams/state/shapes.js	0.00% <0.00%> (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/stateDb.js	0.00% <0.00%> (ø)

... and 1 file with indirect coverage changes