bug: State diagram fix classes type

[weedySeaDragon]

📑 Summary

After merging PR #3648 , mermaidAPI expected stateDb getClasses() to return a {}, not []

(classDefs for state diagrams was no longer working after merging 3648)

Resolves #1952

📋 Tasks

Make sure you

• 📖 have read the contribution guidelines
• 💻 have added unit/e2e tests (if appropriate)
• 🔖 targeted develop branch

[sidharthv96]

Is this a problem?

[weedySeaDragon]

Ya - mermaidAPI createUserStyles expects a Record<string, DiagramStyleClassDef> but stateDb classes was passing it a [].
The result is that mermaidAPI thought that the list of state diagram classes (classDefs) was empty since it couldn't handle the Array.

One day we should create a class to handle the list that __db files return from getClasses(). Then diagrams 'only' have to handle parsing to get classDefs.

[sidharthv96]

I meant this piece of code 😅

I have a faint recollection of doing a similar fix before. Or did I break it? 😬

[weedySeaDragon]

Good catch! I didn't see this.
Ya - at least the line diagramClasses = ... is required because the renderer's getClasses() method is called before draw during mermaidAPI's render(). (Thus diagramClasses needs to be initialized before draw() is called.

You didn't break it. I did. When I did the PR for implementing classDefs in state diagrams, [] worked fine. But when I DRY-ed mermaidAPI (PR #3648) , I broke it -- and because it didn't have any tests to catch it, it went through.

I'll add some tests to this PR so this will be caught if it happens again. (I should've added them to begin with.) I'll change the status of this PR to draft until I've got them submitted and it's ready for review again so that no one thinks it's ready to merge.

[weedySeaDragon]

Ready for another review, @sidharthv96.

Here's the summary of what I did:

• in stateRenderer-v2:

  • the diagramClasses global is no longer needed because mermaidAPI has been cleaned up. mermaidAPI used to call getClasses() repeatedly and so diagramClasses was used to memoize/cache the value.
  • the diagramStates global is now local to render() and passed to other functions as needed

• created a spec for stateRenderer-v2. Right now it only has 1 tiny test, but I defined a FauxDiagram class, so that is ready to be used to write more tests for the renderer.

• (minor) fixed a few jsdoc param and return types

[sidharthv96]

Nice!!