Architecture

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JHGrid (public API + event handling)
  ├── DataManager  (chunk cache, async fetch, prefetch)
  └── Renderer     (Canvas 2D drawing: header, cells, scrollbars)

Virtual rendering flow

scroll event
  → compute visible row/col range from scrollTop / scrollLeft
  → DataManager.getRow(r) → cache hit → value
                           → cache miss → trigger async fetch, return null ("…")
  → Renderer draws only the ~30–60 visible cells per frame
  → on chunk loaded → re-render

Advanced / low-level exports

These are exported mainly for building tooling around JHGrid (a custom exporter, an alternate render surface) rather than for everyday app code; most consumers never need them:

• Renderer / DataManager: the two internal classes above, exported so advanced code can drive the canvas-drawing or chunk-caching logic independently of a full JHGrid instance.
• DEFAULT_THEME: the fully-resolved theme object every GridTheme partial is merged against (i.e. every default value listed in Theming, as one object).
• computeHeaderCells(headerRows, columns): the same merged-header layout engine the canvas header draw uses internally, exposed so a custom exporter (e.g. one writing to a spreadsheet format) can reproduce identical multi-level header spans instead of re-deriving them.

TypeScript type declarations aren’t included in this distribution yet (npm package with index.d.ts is coming soon); for now, these are documented by name only; check the exported symbols directly (e.g. console.log(Object.keys(await import('../dist/jhgrid.esm.js')))) for their exact shape.