Lazy-load expand on demand

Live in demo 31-lazy-tree-load.

When

Tree rows where children are fetched only when the user expands their parent.

How

Key API surface:

• onExpand callback
• merge children into $state on resolve

See the demo source for the full implementation; this recipe pins the pattern + the surface so you can copy-paste it confidently. The doc page that explains the underlying feature in depth is linked from the recipes index.

See also

• Demo 31-lazy-tree-load source
• Demo 31-lazy-tree-load prompt sidecar - drop into an LLM context window
• Recipes index